Samacheer Kalvi 9th Maths Guide Chapter 3 Algebra Ex 3.15

Students can download Maths Chapter 3 Algebra Ex 3.15 Questions and Answers, Notes, Samacheer Kalvi 9th Maths Guide Pdf helps you to revise the complete Tamilnadu State Board New Syllabus, helps students complete homework assignments and to score high marks in board exams.

Tamilnadu Samacheer Kalvi 9th Maths Solutions Chapter 3 Algebra Ex 3.15

Multiple Choice Questions.

Question 1.
If x3 + 6x2 + kx + 6 is exactly divisible by x + 2, then k = 2
(a) 6
(b) -7
(c) -8
(d) 11
Solution:
(d) 11
Hint:
p(x) = x3 + 6x2 + kx + 6
Given p(-2) = 0
(-2)3 + 6(-2)2 + k(-2) + 6 = 0
-8 + 24 – 2k + 6 = 0
22 – 2k = 0
k = \(\frac{22}{2}\)
= 11

Question 2.
The root of the polynomial equation 2x + 3 = 0 is…….
(a) \(\frac{1}{3}\)
(b) –\(\frac{1}{3}\)
(c) –\(\frac{3}{2}\)
(d) –\(\frac{2}{3}\)
Solution:
(c) –\(\frac{3}{2}\)
Hint:
2x + 3 = 0
2x = – 3 ⇒ x = –\(\frac{3}{2}\)

Online Polynomial Root Calculator. This online tool calculates the roots of a polynomial. I use this tool to calculate the roots to plot Bode diagrams.

Samacheer Kalvi 9th Maths Guide Chapter 3 Algebra Ex 3.15

Question 3.
The type of the polynomial 4 – 3x3 is ……..
(a) constant polynomial
(b) linear polynomial
(c) quadratic polynomial
(d) cubic polynomial
Solution:
(d) cubic polynomial

Question 4.
If x51 + 51 is divided by x + 1, then the remainder is …….
(a) 0
(b) 1
(c) 49
(d) 50
Solution:
(d) 50
Hint:
p(x) = x51 + 51
p(-1)= (-1)51 + 51
= -1 + 51
= 50

Question 5.
The zero of the polynomial 2x + 5 is ……..
(a) \(\frac{5}{2}\)
(b) –\(\frac{5}{2}\)
(c) \(\frac{2}{5}\)
(d) –\(\frac{2}{5}\)
Solution:
(b) –\(\frac{5}{2}\)
Hint:
2x + 5 = 0 ⇒ 2x = -5 ⇒ x = –\(\frac{5}{2}\)

Samacheer Kalvi 9th Maths Guide Chapter 3 Algebra Ex 3.15

Question 6.
The sum of the polynomials p(x) = x3 – x2 – 2, q(x) = x2 – 3x + 1
(a) x3 – 3x – 1
(b) x3 + 2x2 – 1
(c) x3 – 2x2 – 3x
(d) x3 – 2x2 + 3x – 1
Solution:
(a) x3 – 3x – 1
Hint:
p(x) + q(x) = (x3 – x2 – 2) + (x2 – 3x + 1) = x3 – x2 – 2 + x² – 3x + 1
= x³ – 3x – 1

Question 7.
Degree of the polynomial (y³ – 2) (y³ + 1) is
(a) 9
(b) 2
(c) 3
(d) 6
Solution:
(d) 6
(y³ – 2) (y³ + 1) = y6 + y³ – 2y³ – 2
= y6 – y³ – 2

Question 8.
Let the polynomials be
(A) -13q5 + 4q² + 12q
(B) (x² + 4)(x² + 9)
(C) 4q8 – q6 + q²
(D) –\(\frac{5}{7}\) y12 + y³ + y5.
Then ascending order of their degree is
(a) A, B, D, C
(b) A, B, C, D
(c) B, C, D, A
(d) B, A, C, D
Solution:
(d) B, A, C, D

Samacheer Kalvi 9th Maths Guide Chapter 3 Algebra Ex 3.15

Question 9.
If p(a) = 0 then (x – a) is a …….. of p(x)
(a) divisor
(b) quotient
(c) remainder
(d) factor
Solution:
(d) factor

Question 10.
Zeros of (2 – 3x) is ……..
(a) 3
(b) 2
(c) \(\frac{2}{3}\)
(d) \(\frac{3}{2}\)
Solution:
(c) \(\frac{2}{3}\)

Question 11.
Which of the following has x -1 as a factor?
(a) 2x – 1
(b) 3x – 3
(c) 4x – 3
(d) 3x – 4
Solution:
(b) 3x – 3

Samacheer Kalvi 9th Maths Guide Chapter 3 Algebra Ex 3.15

Question 12.
If x – 3 is a factor of p(x), then the remainder is ……..
(a) 3
(b) -3
(c) p(3)
(d) p(-3)
Solution:
(c) p(3)

Question 13.
(x +y)(x² – xy + y²) is equal to ……..
(a) (x + y)³
(b) (x – y)³
(c) x³ + y³
(d) x³ – y³
Solution:
(c) x³ + y³

Question 14.
(a + b – c)² is equal to ……..
(a) (a – b + c)²
(b) (-a – b + c)²
(c) (a + b + c)²
(d) (a – b – c)²
Solution:
(b) (-a – b + c)²
Hint:
(a + b – c)² = a² + b² + c² + 2ab – 2bc – 2ac
(- a – b + c)² = a² + b² + c² + 2ab – 2bc – 2ac
(OR)
(- a – b + c)² = (-1)² (a + b + c)² (taking – 1 as common)
= (a + b – c)²

Samacheer Kalvi 9th Maths Guide Chapter 3 Algebra Ex 3.15

Question 15.
In an expression ax² + bx + c the sum and product of the factors respectively ……..
(a) a, bc
(b) b, ac
(c) ac, b
(d) bc, a
Solution:
(b) b, ac

Question 16.
If (x + 5) and (x – 3) are the factors of ax² + bx + c, then values of a, b and c are ………
(a) 1, 2, 3
(b) 1, 2, 15
(c) 1, 2, -15
(d) 1, -2, 15
Solution:
(c) 1, 2, -15
Hint:
(x + 5) (x – 3) = x² + (5 – 3) x + (5) (-3)
= x² + 2x – 15
compare with ax² + bx + c
a = 1, b = 2 and c = -15

Question 17.
Cubic polynomial may have maximum of ……… linear factors.
(a) 1
(b) 2
(c) 3
(d) 4
Solution:
(c) 3

Samacheer Kalvi 9th Maths Guide Chapter 3 Algebra Ex 3.15

Question 18.
Degree of the constant polynomial is ……..
(a) 3
(b) 2
(c) 1
(d) 0
Solution:
(d) 0

Question 19.
Find the value of m from the equation 2x + 3y = m. If its one solution is x = 2 and y = -2.
(a) 2
(b) -2
(c) 10
(d) 0
Solution:
(b) – 2
Hint:
The equation is 2x + 3y = m
Substitute x – 2 and y = -2 we get
2(2) + 3(-2) = m ⇒ 4 – 6 = m ⇒ -2 = m

Question 20.
Which of the following is a linear equation?
(a) x + \(\frac{1}{2}\) = 2
(b) x (x – 1) = 2
(c) 3x + 5 = \(\frac{2}{3}\)
(d) x³ – x = 5
Solution:
(c) 3x + 5 = \(\frac{2}{3}\)

Samacheer Kalvi 9th Maths Guide Chapter 3 Algebra Ex 3.15

Question 21.
Which of the following is a solution of the equation 2x – y = 6?
(a) (2, 4)
(b) (4, 2)
(c) (3, -1)
(d) (0, 6)
Solution:
(b) (4, 2)
Hint:
2x – y = 6
Substitute x – 4 and y = 2 we get
2(4) – 2 = 6 ⇒ 8 – 2 = 6 ⇒ 6 = 6
∴ (4, 2) is the solution

Question 22.
If (2, 3) is a solution of linear equation 2x + 3y = k then, the value of k is ……..
(a) 12
(b) 6
(c) 0
(d) 13
Solution:
(d) 13
Hint:
The equation is 2x + 3y = k
Substitute x = 2 and y = 3 we get,
2(2) + 3(3) = k ⇒ 4 + 9 = k ⇒ 13 = k

Question 23.
Which condition does not satisfy the linear equation ax + by + c = 0 ……..
(a) a ≠ 0, b = 0
(b) a = 0, b ≠ 0
(c) a = 0, b = 0, c ≠ 0
(d) a ≠ 0, b ≠ 0
Solution:
(c) a = 0, b = 0, c ≠ 0

Samacheer Kalvi 9th Maths Guide Chapter 3 Algebra Ex 3.15

Question 24.
Which of the following is not a linear equation in two variable?
(a) ax + by + c = 0
(b) 0x + 0y + c = 0
(c) 0x + by + c = 0
(d) ax + 0y + c = 0
Solution:
(b) 0x + 0y + c = 0
Hint:
0x + 0y + c = 0
0 + 0 + c = 0 ⇒ c = 0
There is no variable.
∴ It is not a linear equation

Question 25.
The value of k for which the pair of linear equations 4x + 6y – 1 = 0 and 2x + ky – 1 = 0 represents parallel lines is ……..
(a) k = 3
(b) k = 2
(c) k = 4
(d) k = -3
Solution:
(a) k = 3
Hint:
Slope of 4x + 6y – 1 = 0 is
6y = -4x + 1 ⇒ y = \(\frac{-4}{6}\) x + \(\frac{1}{6}\)
Slope = \(\frac{-4}{6}\) = \(\frac{-2}{3}\)
Slope of 2x + ky – 7 = 0
ky = -2x + 7
y = \(\frac{-2}{k}\)x + \(\frac{7}{k}\)
Slope of a line = \(\frac{-2}{k}\)
Since the lines are parallel
\(\frac{-2}{3}\) = \(\frac{-2}{k}\)
-2k = – 6
k = \(\frac{6}{2}\)
= 3

Samacheer Kalvi 9th Maths Guide Chapter 3 Algebra Ex 3.15

Question 26.
A pair of linear equations has no solution then the graphical representation is ……..
Samacheer Kalvi 9th Maths Guide Chapter 3 Algebra Ex 3.15 1
Solution:
Samacheer Kalvi 9th Maths Guide Chapter 3 Algebra Ex 3.15 2
Hint:
Since there is no solution the two lines are parallel. (l11m)

Question 27.
If \(\frac{a_1}{a_2}\) ≠ \(\frac{b_1}{b_2}\) where a1x + b1y + c1 = 0 and a2x + b2y + c2 = 0 then the given pair of linear equation has …….. solution(s).
(a) no solution
(b) two solutions
(c) unique
(d) infinite
Solution:
(c) unique
Hint:
Since it has unique solution
\(\frac{a_1}{a_2}\) ≠ \(\frac{b_1}{b_2}\)

Samacheer Kalvi 9th Maths Guide Chapter 3 Algebra Ex 3.15

Question 28.
\(\frac{a_1}{a_2}\) = \(\frac{b_1}{b_2}\) ≠ \(\frac{c_1}{c_2}\) where a1x + b1y + c1 = 0 and a2x + b2y + c2 = 0 then the given pair of linear equation has …….. solution(s).
(a) no solution
(b) two solutions
(c) infinite
(d) unique
Solution:
(a) no solution
Hint:
\(\frac{a_1}{a_2}\) = \(\frac{b_1}{b_2}\) ≠ \(\frac{c_1}{c_2}\) the linear equation has no solution.

Question 29.
GCD of any two prime numbers is …….
(a) -1
(b) 0
(c) 1
(d) 2
Solution:
(c) 1

Samacheer Kalvi 9th Maths Guide Chapter 3 Algebra Ex 3.15

Question 30.
The GCD of x4 – y4 and x² – y² is ……..
(a) x4 – y4
(b) x² – y²
(c) (x + y)²
(d) (x + y)4
Solution:
(b) x² – y²
Hint:
x4 – y4 = (x²)² – (y²)²
= (x² + y²)(x² – y²)
x² – y² = (x² – y²)
G.C.D. = x² – y²

Samacheer Kalvi 9th Science Guide Chapter 2 Motion

Tamilnadu State Board New Syllabus Samacheer Kalvi 9th Science Guide Pdf Chapter 2 Motion Text Book Back Questions and Answers, Notes.

Tamilnadu Samacheer Kalvi 9th Science Solutions Chapter 2 Motion

9th Science Guide Motion Text Book Back Questions and Answers

I. Choose the correct answer:

Online Average Acceleration calculator can be used to calculate Acceleration,​initial and final velocity and time taken.

Question 1.
The area under velocity – time graph represents the
(a) velocity of the moving object.
(b) displacement covered by the moving object,
(c) speed of the moving object.
(d) acceleration of the moving object.
Answer:
(b) displacement covered by the moving object

Samacheer Kalvi 9th Science Guide Chapter 2 Motion

Question 2.
Which one of the following is most likely not a case of uniform circular motion?
(a) Motion of the Earth around the Sim.
(b) Motion of a toy train on a circular track.
(c) Motion of a racing car on a circular track.
(d) Motion of hours’ hand on the dial of the clock.
Answer:
(c) Motion of a racing car on a circular track

Question 3.
Which of the following graph represents uniform motion of a moving particle?
Samacheer Kalvi 9th Science Guide Chapter 2 Motion 1
Samacheer Kalvi 9th Science Guide Chapter 2 Motion 2
Answer:
Samacheer Kalvi 9th Science Guide Chapter 2 Motion 3

Samacheer Kalvi 9th Science Guide Chapter 2 Motion

Question 4.
The centrifugal force is
(a) a real force.
(b) the force of reaction of centripetal force.
(c) a virtual force.
(d) directed towards the centre of the circular path.
Answer:
(c) a virtual force

II. Fill in the blanks :

1. Speed is a …………………….quantity whereas velocity is a …………….quantity.
Answer:
Scalar, Vector

2. The slope of the distance – time graph at any point gives ………………
Answer:
Speed

Samacheer Kalvi 9th Science Guide Chapter 2 Motion

3. Negative acceleration is called ……………………
Answer:
retardation (or) deceleration

Displacement calculator is really a nice calculator that will help you solve a lot of your problems related to displacement.

4. Area under velocity – time graph shows ……………………………….
Answer:
displacement

III. State whether true or false. If false, correct the statement:

1. The motion of a city bus in a heavy traffic road is an example for uniform motion.
Answer:
False.
Correct statement: The motion of a city bus in a heavy traffic road is an example for non-uniform motion.

2. Acceleration can get negative value also.
Answer:
True.

Samacheer Kalvi 9th Science Guide Chapter 2 Motion

3. Distance covered by a particle never becomes zero but displacement becomes zero.
Answer:
True.

4. The velocity – time graph of a particle falling freely under gravity would be a straight line parallel to the x axis. .
Answer:
False.
Correct statement: The velocity – time graph of aparticle moving at uniform do dry. would be straight line parallel to the x axis.

5. If the velocity – time graph of a particle is a straight line inclined to X-axis then its displacement – time graph will be a straight line.
Answer:
True.

IV. Assertion and Reason Type Questions :

Mark the correct choice as:
(a) If both assertion and reason are true and reason is the correct explanation of assertion.
(b) If both assertion and reason are true but reason is not the correct explanation of assertion.
(c) If assertion is true but reason is false.
(d) If assertion is false but reason is true.

Samacheer Kalvi 9th Science Guide Chapter 2 Motion

Question 1.
Assertion : The accelerated motion of an object may be due to change in magnitude of velocity or direction or both of them..
Reason : Acceleration can be produced only by change in magnitude of the velocity. It does not depend the direction.
Answer:
(c) If assertion is true but reason is false.

Use Average Velocity Calculator to find the average velocity, initial velocity, and final velocity with average velocity formula (vavg=(v+u)/2).

Question 2.
Assertion : The Speedometer of a car or a motor-cycle measures its average speed.
Reason : Average velocity is equal to total displacement divided by total time taken.
Answer:
(d) Assertion is false but reason is true

Question 3.
Assertion : Displacement of a body may be zero when distance travelled by it is not zero.
Reason : The displacement is the shortest distance between initial and final position.
Answer:
(a) Both assertion and reason are true and reason is the correct explanation of assertion

Samacheer Kalvi 9th Science Guide Chapter 2 Motion

V. Match the Following :

Samacheer Kalvi 9th Science Guide Chapter 2 Motion 4
Answer:
Samacheer Kalvi 9th Science Guide Chapter 2 Motion 5

Samacheer Kalvi 9th Science Guide Chapter 2 Motion

VI. Answer briefly :

Question 1.
Define velocity.
Answer:
Velocity is the rate of change of displacement. It. is the displacement in unit time.

Question 2.
Distinguish distance and displacement.
Answer:
Table
Distance

  1. The actual length of the path travelled by a moving body irrespective of the direction
  2. It is a Scalar quantity

Displacement:

  1. The change in position of a moving body in a particular direction
  2. It is a Vector quantity

Question 3.
What do you mean by uniform-motion?
Answer:
An object is said to be in uniform motion if it covers equal distances in equal intervals of time how so ever big or small these time intervals may be.

Samacheer Kalvi 9th Science Guide Chapter 2 Motion

Question 4.
Compare speed and velocity.
Answer:

Speed Velocity
1. It is the rate of change of distance with respect to time It is the rate of change of displacement with respect to time
2. It is a scalar quantity having magnitude only It is a vector quantity having both magnitude and direction
3. Speed is velocity without a particular direction Velocity is speed in a particular direction
4. It is measured in ms-1 in SI system It is also measured in ms-1 in a particular direction in SI system
5. Speed in any direction would be a positive quantify, since the distance in any direction is a positive quantity. Velocity can get both positive and negative values. If velocity in one direction is assumed to be positive then the velocity in the opposite direction would be a negative quantity. Velocity can get zero value also.

Question 5.
What do you understand about negative acceleration?
Answer:
If v < u, i.e. if final velocity is less than initial velocity, the velocity decreases with time and the value of acceleration is negative. It is called negative acceleration. It is also called as retardation (or) deceleration.

Question 6.
Is the uniform circular motion accelerated? Give reasons for your answer.
Answer: When an object is moving with a constant speed along a circular path, the change in velocity is only due to the change in direction. Hence it is accelerated motion.

Samacheer Kalvi 9th Science Guide Chapter 2 Motion

Question 7.
What is meant by uniform circular motion? Give two examples of uniform circular motion.
Answer:
When an object moves with constant speed along a circular path, the motion is called uniform circular motion.
Example :

  • The earth moves around the sun in the uniform circular motion.
  • The moon moves in uniform circular motion around the earth.

VII. Answer in detail :

Question 1.
Derive the equations of motion by graphical method.
Answer:
Equations of motion from velocity-time graph:
Samacheer Kalvi 9th Science Guide Chapter 2 Motion 6

Graph shows the change in velocity with time of a uniformly accelerated object. The object starts from the point D in the graph with velocity u. Its velocity keeps increasing and after time t it reaches the point B on the graph.
The initial velocity of the object = u = OD = EA
The final velocity of the object = v = OC = EB
Time = t = OE = DA
Also from the graph we know that, AB = DC

Samacheer Kalvi 9th Science Guide Chapter 2 Motion

1. First equation of motion :

By definition, acceleration = change in velocity / time
= (final velocity – initial velocity)/time
= (OC – OD) / OE
= DC / OE
a = DC /t
DC = AB = at
From the graph EB = EA + AB
v = u + at…………..(1)
This is first equation of motion. .

2. Second equation on of motion :
From the graph the distance covered by the object during time t is given by the area of quadrangle DOEB

s = area of the quadrangle DOEB
= area of the rectangle DOEA + area of the triangle DAB
= (AE x OE) + (1/2 × AB × DA) .
s = ut + 1/2 (at2) …………(2)
This is the second equation of motion.

Samacheer Kalvi 9th Science Guide Chapter 2 Motion

3. Third equation of motion :
From the graph the distance covered by the object during time, t is given by the area of the quadrangle DOEB. Here DOEB is a trapezium. Then,
s = area of trapezium DOEB
= 1/2 × sum of length of parallel side × distance between parallel sides
= 1/2 × (OD + BE) × OE
S = 1/2 ×× (u + v) × t
since a = (v – u) /1 or t = (v – u) / a
Therefore s = 1/2 × (v + u) x (v – u) / a
2as = v2 – u2
v2 = u2 + 2 as …………….. (3)
This is the third equation of motion.

Question 2.
Explain different types of motion.
Answer:
In physics, motion can be classified as below.

1. Linear motion: Motion along a straight line.

2. Circular motion: Motion along a circular path.

3. Oscillatory motion: Repetitive to and fro motion of an object at regular intervals of time. Random motion: Motion of the object which does not fall in any of the above categories.

Uniform and Non-uniform motion:

Uniform motion: Consider a car that covers 60 km in the first hour, 60 km in the second horn-, and another 60 km in the third hour, and so on. The car covers equal distance at equal intervals of time. We can say that the motion of the car is uniform. An object is said to be in uniform motion if it covers equal distances in equal intervals of time howsoever big or small these time intervals may be.

Non-uniform motion: Now, consider a bus starting from one stop. It proceeds slowly when it passes through a crowded area of the road. Suppose, it manages to travel merely 100 m in 5 minutes due to heavy traffic and is able to travel about 2 km in 5 minutes when the road is clear. Hence, the motion of the bus is non-uniform i.e. it travels unequal distances in equal intervals of time.

VIII. Exercise Problems:

Question 1.
A ball is gently dropped from a height of 20 m. If its velocity increases uniformly at the rate of 10ms-2, with what velocity will it strike the ground? After what time will it strike the ground?
Answer:
Here we have
Initial velocity, u = 0
Distance, s = 20 m
Acceleration, a = 10 m/s2
Final velocity, v = ?
Time, t = ?

a) Calculation of final velocity, v
We know that, v2 = u2 + 2as
v2 = 0 + 2 × 10m/s2 × 20m
v2 = 400m2/s2
\(=\sqrt{400 m^{2} / s^{2}}\)
v = 20m/s

b) Calculation of time, t
We know that, v = u + at
20 m/s = 0 + 10m/s2 × t
t = \(\frac{20 m / s^{2}}{20 m / s}=2 s\)
∴ Ball will strike the ground at a velocity of 20 ms-1
Time taken to reach the ground = 2s.

Samacheer Kalvi 9th Science Guide Chapter 2 Motion

Question 2.
An athlete completes one round of a circular track of diameter 200 m in 40 s. What will be the distance covered and the displacement at the end of 2 m and 20 s?
Answer:
Here we have
Diameter = 200. m
∴ Radius = 200 m/2 = 100 m
Time of one rotation = 40 s
Time after 2m 20 s = 2 × 60 s +20 s = 140 s
Distance after 140 s = ?
Displacement after 140 s = ?
Circular track with a diameter of 200m
We know that, velocity
Samacheer Kalvi 9th Science Guide Chapter 2 Motion 7
Samacheer Kalvi 9th Science Guide Chapter 2 Motion 8

a) Distance after 140 s
We know that, distance = velocity × time
= Distance 15.7 rn/s × 140 s
= 2198m

Samacheer Kalvi 9th Science Guide Chapter 2 Motion

b) Displacement after 2 min 20 s i.e, in 140 s
We know that, distance = velocity × time
Since, rotation in 40 s = 1
∴ Rotation in 1 s = \(\frac{1}{40}\)
∴ Rotation in 140 s = \(\frac{1}{40} \times 140=3.5\)
∴ In 3.5 rotation athlete will be just at the opposite side of the circular track,
i.e. at a distance equal to the diameter of the circular track which is equal to 200m
∴ Distance covered in 2min 20 s = 2198 m
Displacement after 2min 20 5 = 200 m.

Question 3.
A racing car has a uniform acceleration of 4ms-2. What distance it covers in 10s after the start?
Answer:
Here we have
Acceleration, a = 4 m/s2.
Initial velocity u = 0
Time t = 10 s
Distance (s) covered =?
We know that, s = ut + \(\frac { 1 }{ 2 }\) at2
s = (0 × 10s) + [\(\frac { 1 }{ 2 }\) × 4 m/s2 × (10 s)2]
= \(\frac { 1 }{ 2 }\) × 4 m/s2 × 100 s2
= 2 × 100 m = 200 m

Thus, racing car will cover a distance of 200 m after start in 10s with given acceleration.

Samacheer Kalvi 9th Science Guide Chapter 2 Motion

Intex Activities

ACTIVITY – 1

Look around you. You can see many things: a row of houses, large trees, small plants, flying birds, running cars and many more. List the objects which remain fixed at their position and the objects which keep on changing their position.
Solution:

  1. Row of houses, large trees, small plants are the examples, of immovable objects.
  2. Flying birds, running cars and buses are the examples of movable objects.

Activity to be done by the students themselves

ACTIVITY – 2

Tabulate the distance covered by a bus in a heavy traffic road in equal intervals of time and do the same for a train which is not in an accelerated motion. From your table what do you understand?
The bus covers unequal distance in equal intervals of time but the train covers equal distances in equal intervals of time.
Solution:
Samacheer Kalvi 9th Science Guide Chapter 2 Motion 9

Samacheer Kalvi 9th Science Guide Chapter 2 Motion

ACTIVITY – 3

Observe the motion of a car as shown in the figure and answer the following questions:
Compare the distance covered by the car through the path ABC and AC. What do you observe? Which path gives the shortest distance to reach D from A? Is it the path ABCD or the path ACD or the path AD?
Samacheer Kalvi 9th Science Guide Chapter 2 Motion 10
Solution:

  1. Distance covered by the car through the path ABC = 4m + 3m = 7 m. and AC = 5 m. The distance covered by the car through the path ABC is large compared to AC.
  2. The shortest distance to resell D from A is path AD = 3m.
  3. The total distance covered by the car ABCD A = 14 m. It finally reaches to A.

Samacheer Kalvi 9th Science Guide Chapter 2 Motion

ACTIVITY – 4

Take a large stone and a small eraser. Stand on the top fit a table and drop them simultaneously from the same height? What do you observe? Now, take a small eraser and a sheet of paper. Drop them simultaneously from the same height. What do you observe? This time, take two sheets of paper having same mass and crumple one of the sheets into a ball. Now, drop the sheet and the ball from the same height. What do you observe?
Solution :
Both the stone and the eraser have reached the surface of the earth almost at the same time.
The eraser reaches first and the sheet of paper reaches later.
The paper crumpled into a ball reaches ground first and plain sheet of paper reaches later, although they have equal mass. It is because of air resistance. The magnitude of air resistance despends on the area of object exposed to air. So the sheet of paper reaches later.

Samacheer Kalvi 9th Science Guide Chapter 2 Motion

9th Science Guide Motion Additional Important Questions and Answers

I. Choose the correct answer :

Question 1.
A particle is moving in a circular pattern of radius r. The displacement after half a circle would be
(a) zero
(b) πr
(c) 2r
(d) 2πr
Answer:
(c) 2r

Question 2.
In which of the following cases of motions, the distance moved and the magnitude of displacement are equal?
(a) If the car is moving in the straight road.
(b) If the car is moving in a circular road.
(c) The earth is revolving around the sun.
(d) The pendulum is moving to and fro
Answer:
(a) If the car is moving in the straight road

Samacheer Kalvi 9th Science Guide Chapter 2 Motion

Question 3.
A body is thrown vertically upward with velocity, the greatest height h to which it will rise is
(a) u2/2g
(b) u2/g
(c) u/g
(d) u/2g
Answer:
(a) u2/2g

Question 4.
If the displacement of an object is proportional to square of time, then the object moves with
(a) uniform velocity
(b) uniform acceleration
(c) increasing acceleration
(d) decreasing acceleration
Answer:
(b) uniform acceleration

Samacheer Kalvi 9th Science Guide Chapter 2 Motion

Question 5.
From the given v-t graph, u can be inferred that the object is
(a) in uniform motion
(b) at rest
(c) in non-uniform motion
(d) moving with uniform acceleration
Answer:
(a) in uniform motion

Question 6.
The area under v-t graph represents a physical quantity which has the unit.
(a) m2
(b) m
(c) m3
(d) ms-1
Answer:
(b) m

Question 7.
m/s2 is the unit of
(a) distance
(b) displacement
(c) velocity
(d) acceleration
Answer:
(d) acceleration

Samacheer Kalvi 9th Science Guide Chapter 2 Motion

Question 8.
The rate of change of displacement
(a) speed
(b) velocity
(c) acceleration
(d) retardation
Answer:
(b) velocity

Question 9.
A scalar quantity has T
(a) magnitude only
(b) direction only
(c) both
(d) none
Answer:
(a) magnitude only

Samacheer Kalvi 9th Science Guide Chapter 2 Motion

Question 10.
When an object undergoes acceleration
(a) there is always an increase in its velocity
(b) there is always an increase in its speed
(c) a force always acting on it.
(d) all of the above
Answer:
(c) a force always acting on it

Question 11.
A body is projected up with an initial velocity u m/s. It goes up to a height, ‘h’ metres in seconds time. Then it comes back at the point of projection. Considering negligible air resistance, which of the following statement is true?
(a) the acceleration is zero
(b) the displacement is zero
(c) the average velocity is 2hit
(d) the final velocity is 2u when body reaches projection point
Answer:
(b) the displacement is zero

Samacheer Kalvi 9th Science Guide Chapter 2 Motion

Question 12.
A car accelerates at 1.5m/s2in a straight road. How much is the increase in velocity in 4s.
(a) 6 m/s
(b) 4 m/s
(c) 3 m/s
(d) 2.66 m/s
Answer:
(a) 6 m/s

Question 13.
The slope of the distance-time curve is steeper / greater is the
(a) velocity
(b) acceleration
(c) displacement
(d) speed
Answer:
(d) speed

Question 14.
The given graph represents motion with …………….speed.
Samacheer Kalvi 9th Science Guide Chapter 2 Motion 11
(a) uniform
(b) non-uniform
(c) constant
(d) none
Answer:
(b) non-uniform

Samacheer Kalvi 9th Science Guide Chapter 2 Motion

Question 15.
The relation between displacemeñt and time is given by the equation of
(a) v2 = ut + at
(b) s = ut + \(\frac { 1 }{ 2 }\) at2
(e) c = s/t
(d) v2 = u2 + 2as
Answer:
(b) s = ut + \(\frac { 1 }{ 2 }\) at2

Question 16.
A body moves in a uniform circular motion
(a) It is moving with constant velocity
(b) its acceleration is zero
(c) the body has an acceleration y
(d) none of the above
Answer:
(a) It is moving with constant velocity

Question 17.
Speed of the body in particular direction can be called
(a) acceleration
(b) displacement
(c) velocity
(d) distance
Answer:
(c) velocity

Samacheer Kalvi 9th Science Guide Chapter 2 Motion

Question 18.
Statement A: Uniform circular motion is a case of accelerated motion
Statement B: In third equation of motion we do not have the term time
(a) Statement B is true, A is false
(b) Statement A is true, B is false
(c) neither statement A nor B is true
(d) both are true
Answer:
(d) both are true

Question 19.
Which of the following is correct about uniform circular motion
(i) direction of motion is continuously changed
(ii) direction of motion is not changed
(iii) speed and direction both remain constant
(iv) speed is constant but direction is changing
(a) ii & iii are correct
(b) i, ii & iii are correct
(c) i & iv are correct
(d) all of these
Answer:
(c) i & iv are correct

Question 20.
Which of the quantities have the same SI unit?
(a) speed, velocity
(b) acceleration, time
(c) velocity, time
(d) velocity, acceleration
Answer:
(a) speed, velocity

Samacheer Kalvi 9th Science Guide Chapter 2 Motion

Question 21.
Rest and motion of body are
(a) non-relative
(b) not related
(c) relative
(d) none
Answer:
(c) relative

Question 22.
An ant moves from one corner of a room diagonally to the opposite corner. If the dimensions of the hall are 8m x 6m, the displacement of the ant is
(a) 10m
(b) 14m
(c) 28m
(d) 2m
Answer:
(a) 10m

Samacheer Kalvi 9th Science Guide Chapter 2 Motion

Question 23.
The displacement covered by a second hand of radius V in a clock after one revolution is
(a) 360°
(b) 0
(c) 3r
(d) 2r
Answer:
(b) 0

Question 24.
A man leaves his house at 6.30 a.m. for a morning walk and returns back at 7.30 a.m. after covering 4 km. Displacement covered by him is …………….
(a) 2 km
(b) zero
(c) 8 km
(d) 4 km
Answer:
(b) zero

Question 25.
A body is said to be in non uniform motion if it travels
(a) equal distance in unequal interval of time
(b) equal distance in equal interval of time
(c) unequal distance in unequal interval of time
(d) unequal distance in equal interval of time.
Answer:
(d) unequal distance in equal interval of time

Question 26.
A quantity which has both magnitude and direction is
(a) scalar
(b) distant
(c) vector
(d) moving body
Answer:
(c) vector

Question 27.
A bus accelerating with 4ms-2 changes its speed from 60ms_1 to a certain value in 5s. The final speed is
(a) 40 m/s
(b) 25 ms-1
(c) 60 ms-1
(d) 30 ms-1
Answer:
(a) 40 m/s

Samacheer Kalvi 9th Science Guide Chapter 2 Motion

Question 28.
A quantity has a value of 16ms-2. It is the
(a) acceleration of an object
(b) velocity of an object
(c) retardation of an object
(d) speed of an object
Answer:
(c) retardation of an object

Question 29.
A boy throws a ball up and catches it when the ball falls back. In which part of the motion the ball is accelerating?
(a) during downward motion
(b) when the ball comes to rest
(c) during upward motion
(d) when the boy catches the ball.
Answer:
(a) during downward motion]

Question 30.
Choose the correct option.
(a) distance is a scalar, velocity is a vector, acceleration is a vector
(b) distance is a vector, velocity is a scalar, acceleration is a vector
(c) distance is a vector, velocity is a vector, acceleration is a vector
(d) distance is a scalar, velocity is a vector, acceleration is scalar
Answer:
(a) distance is a scalar, velocity is a vector, acceleration is a vector

Question 31.
If a moving body comes to rest, then its acceleration is
(a) positive
(b) negative
(c) zero
(d) all of these depending upon initial velocity.
Answer:
(b) negative

Samacheer Kalvi 9th Science Guide Chapter 2 Motion

Question 32.
If the velocity of a body changes uniformly from u to v in time t, the sum of average velocity and acceleration is
Samacheer Kalvi 9th Science Guide Chapter 2 Motion 12
Samacheer Kalvi 9th Science Guide Chapter 2 Motion 13
Answer:
Samacheer Kalvi 9th Science Guide Chapter 2 Motion 14

Question 33.
Acceleration is defined as the rate of change of
(a) distance
(b) velocity
(c) speed
(d) displacement
Answer:
(b) velocity

Samacheer Kalvi 9th Science Guide Chapter 2 Motion

Question 34.
When an object undergoes acceleration
(a) there is always an increase in its velocity ‘
(b) there is always an increase in its speed
(c) a force always acting on it.
(d) all the above
Answer:
(c) a force always acting on it

Question 35.
The equation v = u + at gives information as
(a) velocity is a function of time
(b) velocity is a function of position
(c) position is a function of time
(d) position is a function of time and velocity
Answer:
(a) velocity is a function of time

Question 36.
Which of the following can determine the acceleration of a moving object.
(a) area of the velocity-time graph
(b) the slope of the velocity-time graph
(c) area of a distance-time graph
(d) the slope of a distance-time graph
Answer:
(b) slope of the velocity-time graph

Samacheer Kalvi 9th Science Guide Chapter 2 Motion

Question 37.
What is the slope of the body when it moves with uniform velocity?
(a) positive
(b) negative
(c) zero
(d) may be positive or negative
Answer:
(c) zero]

Question 38.
If a body starts from rest, what can be said about the acceleration of the body?
(a) positively accelerated
(b) negative accelerated
(c) uniform accelerated
(d) none of the above
Answer:
(a) positively accelerated

Question 39.
When a body moves uniformly along the circle then
(a) its velocity changes but speed remain the same
(b) its speed changes but velocity remains the same
(c) both speed and velocity changes
(d) both speed and velocity remains same
Answer:
(a) its velocity changes but speed remains the same

Samacheer Kalvi 9th Science Guide Chapter 2 Motion

Question 40.
Distance travelled by a freely falling body is proportional to
(a) mass of the body
(b) square of the acceleration due to gravity
(c) square of the time of fall
(d) time of fall
Answer:
(c) square of the time of fall

Question 41.
If the displacement-time graph of a particle is parallel to the time axis, then velocity of the particle is.
(a) infinity
(b) unity
(c) equal to acceleration
(d) zero
Answer:
(d) zero

Question 42.
In the velocity-time graph, AB shows that the body has
Samacheer Kalvi 9th Science Guide Chapter 2 Motion 15
(a) uniform acceleration
(b) non-uniform retardation
(c) uniform speed
(d) initial velocity OA & is moving with uniform retardation.
Answer:
(d) initial velocity OA & is moving with uniform retardation

Samacheer Kalvi 9th Science Guide Chapter 2 Motion

Question 43.
The magnitude of the centripetal force is given by (F= ….)
Samacheer Kalvi 9th Science Guide Chapter 2 Motion 16
Samacheer Kalvi 9th Science Guide Chapter 2 Motion 17
Answer:
Samacheer Kalvi 9th Science Guide Chapter 2 Motion 18

Question 44.
A body moving with an initial velocity 5ms-1 and accelerates at 2ms -2. Its velocity after 10s is
(a) 20ms-1
(b) 25ms-1
(c) 5ms-1
(d) 22.55ms-1
Answer:
(b) 25ms-1

Samacheer Kalvi 9th Science Guide Chapter 2 Motion

Question 45.
In a 100m race, the winner takes 10s to reach the finishing point. The average speed of the winner is
(a) 5ms-1
b) 20ms-1
c) 40ms-1
d) 10ms-1
Answer:
(d) 10ms-2

Question 46.
The area under the velocity-time graph represents
(a) the velocity of the moving object
(b) displacement covered by the moving object
(c) speed of the moving object.
(d) acceleration of the moving object
Answer:
(b) displacement covered by the moving object

Question 47.
A car is being driven at a speed of 20ms-1 when brakes are applied to bring it to rest in 5 s. The deceleration produced in this case will be
(a) +4ms-2
(b) -4ms-2
(c) -0.25ms-2
(d) +0.25ms-2
Answer:
(b) -4ms-2

Samacheer Kalvi 9th Science Guide Chapter 2 Motion

Question 48.
Unit of acceleration is
(a) ms-1
(b) ms-2
(c) ms
(d) ms2
Answer:
(b) ms-2

Question 49.
The force responsible for drying clothes in a washing machine is …………….
(a) Centripetal force
(b) Centrifugal force
(c) Gravitational force
(d) Electro static force
Answer:
(b) Centrifugal force

II. Fill in the blanks:

1. If a body does not change its position, then it is said to be at …………………
Answer:
rest

2. The back and forth motion of a swing is an ………………… motion.
Answer:
Oscillatory

3. In uniform motion an object travels equal ………………… in ………………… interval of time.
Answer:
distances, equal

Samacheer Kalvi 9th Science Guide Chapter 2 Motion

4. The actual path covered by a body is called …………………
Answer:
distance

5. Displacement is the ………………… distance covered by a body.
Answer:
shortest

6. The motion of the bus is ………………… motion.
Answer:
non-uniform

7. Rate of change of displacement is …………………
Answer:
velocity

8. Speed is a ………………… quantity whereas velocity is a …………………
Answer:
scalar, vector

9. If final velocity is less than initial velocity the acceleration is ………………….
Answer:
negative

Samacheer Kalvi 9th Science Guide Chapter 2 Motion

10. If final velocity is equal to initial velocity the value of acceleration is ………………….
Answer:
zero

11. The slope of the distance-time graph becomes steeper & steeper the speed ………………….
Answer:
increases

12. A straight line parallel to the x-axis in the velocity-time graph, represents the object moves in…………………
Answer:
uniform velocity

Samacheer Kalvi 9th Science Guide Chapter 2 Motion

13. From v-t graph ………………… can be calculated.
Answer:
displacement

14. ………………… measures the instantaneous speed of the automobile.
Answer:
Speedometer

15. Slope of the velocity-time graph gives…………………
Answer:
acceleration

16. The value of acceleration for a body at rest is…………………
Answer:
zero

17. At the highest point, when a body is thrown vertically upwards, the velocity is ………………….
Answer:
zero

Samacheer Kalvi 9th Science Guide Chapter 2 Motion

18. A body moves in a circular pattern the ………………… of velocity does not change but changes.
Answer:
magnitude, direction

19. When a body moves in a circular pattern ………………… acceleration is directed radially towards the centre of the circle.
Answer:
centripetal

20. The separation of cream from milk-hn example for the application of ………………….
Answer:
centrifugal

21. Consider an object is rest at position x = 20m. Then its displacement – time graph will be straight-line ………………… to the time axis.
Answer:
Parallel

Samacheer Kalvi 9th Science Guide Chapter 2 Motion

III. State whether true or false. If false, correct the statement:

1. Displacement can be zero but distance never.
Answer:
True.

2. Time is a vector quantity.
Answer:
False.
Correct statement: Time is a scalar quantity.

3. Displacement magnitude can be greater than the distance travelled by the object.
Answer:
True.

4. If the velocity of the body decreases with time the acceleration is negative and the motion is called decelerated motion.
Answer:
True.

Samacheer Kalvi 9th Science Guide Chapter 2 Motion

5. Acceleration is a scalar.
Answer:
False.
Correct statement: Acceleration is a vector.

6. The area of the velocity-time graph gives the displacement of the body.
Answer:
True.

7. Motion & rest are relative terms.
Answer:
True.

8. An object can be moving with uniform speed but variable acceleration.
Answer:
True.

9. Slope of the distance-time graph indicates the speed.
Answer:
True.

Samacheer Kalvi 9th Science Guide Chapter 2 Motion

10. It is possible to have object moving with uniform velocity but non-uniform acceleration.
Answer:
True.

11. It is possible to have object moving with uniform speed but variable acceleration.
Answer:
False.
Correct statement : It is possible to have object moving with uniform speed but constant acceleration.

12. The force experienced by a boy in the merry-go-round is a centripetal force.
Answer:
False.
Correct statement: The force experienced by a boy in the merry-go-round is a centrifugal force.

13. The initial velocity of a freely falling object is zero as it is released from rest.
Answer:
True.

Samacheer Kalvi 9th Science Guide Chapter 2 Motion

IV. Assertion and Reason Type Questions :

(a) If both assertion & reason are true and the reason is the correct explanation of the assertion.
(b) If both assertion & reason are true but the reason is not correct explanation of the assertion.
(c) If the assertion is true but the reason is false.
(d) If assertion & reason both are false.
(e) If assertion is false but reason is true.

Question 1.
Assertion : A body can have acceleration even if its velocity is zero at a given instant of time.
Reason: A body is momentarily at rest when it reverses its direction of motion.
Answer:
(a) Both assertion & reason are true and the reason is the correct explanation of the assertion

Question 2.
Assertion : If the displacement of the body is zero, the distance covered by it may not be zero.
Reason: Displacement is a vector & distance is a scalar quantity.
Answer:
(a) Both assertion & reason are true and the reason is the correct explanation of the assertion

Samacheer Kalvi 9th Science Guide Chapter 2 Motion

Question 3.
Assertion: An object can have constant speed but the variable velocity
Reason: Speed is a scalar but velocity is a vector.
Answer:
(a) Both assertion & reason are true and the reason is the correct explanation of the assertion

Question 4.
Assertion: The speed of a body can be Negative.
Reason : If the body is moving in the opposite direction of positive motion, then its speed is Negative.
Answer:
(d) Assertion & reason both are false

Question 5.
Assertion : The position-time graph of a uniform motion in one dimension of a body can have Negative slope
Reason : When the speed of body decreases with time then, position-time graph of the moving body has Negative slope.
[Answer:
(c) Assertion is true but the reason is false

Samacheer Kalvi 9th Science Guide Chapter 2 Motion

Question 6.
Assertion: A positive acceleration of a body can be associated with slowing down of the body.
Reason: Acceleration is a vector.
[Answer: (b) Both assertion & reason are true but the reason is not correct explanation of the assertion]

Question 7.
Assertion :A negative acceleration of a body can be associated with speeding up of the body.
Reason: Increase in speed of a moving body is independent of its direction of motion.
Answer:
(b) Both assertion & reason are true but the reason is not the correct explanation of the assertion

Question 8.
Assertion When a body is subjected to a uniform acceleration, it is always moving in a straight line.
Reason: Motion may be straight-line motion or circular motion.
Answer:
(e) Assertion is false but the reason is true

Question 9.
Assertion : Position-time graph of a stationary object is a straight line parallel to time axis. ’
Reason : For a stationary object, position does not change with time.
Answer:
(a) Both assertion & reason are true and the reason is the correct explanation of the assertion

Samacheer Kalvi 9th Science Guide Chapter 2 Motion

Question 10.
Assertion : The slope of distance-time graph of a body moving with high speed is steeper than slope of distance-time graph of a body with low velocity.
Reason: Slope of distance-time graph = speed of the body.
Answer:
(a) Both assertion & reason are true and the reason is the correct explanation of the assertion

V. Answer briefly :

Question 1.
What are centripetal acceleration and centripetal force?
Answer:
When a body moves in a circular pattern the acceleration is directed radially towards the centre of the circle.
The force causing this acceleration is also directed towards the centre of the circle and it is called centripetal force.

Question 2.
Find the magnitude of centripetal force.
Answer:
Consider an object of mass m, moving along a circular path of radius r, with a velocity v, its centripetal acceleration is given by a = v2 / r
Hence, the magnitude of centripetal force is given by,
F = mass x centripetal acceleration
F = mv2 / r

Samacheer Kalvi 9th Science Guide Chapter 2 Motion

Question 3.
What is centrifugal force? Give examples.
Answer:
Force acting on a body away from the centre of circular path is called centrifugal force. Thus centrifugal force is in a direction opposite to the direction of centripetal force. Its magnitude is same as that of centripetal force.
Example : Spin dryer of a washing machine, ride on a merry-go-round.

Question 4.
When an object is thrown upwards, what is true of velocity and acceleration at the highest point of motion of the object?
Answer:

  • Velocity becomes zero
  • Acceleration remains same as g.

Question 5.
Name the two quantities, the slope of whose graph gives (i) speed (ii) acceleration.
Answer:
(i) Distance – Time
(ii) Speed – Time

Question 6.
Define Average speed.
Answer:
It is the total distance travelled divided by the total time taken to cover this distance.
Samacheer Kalvi 9th Science Guide Chapter 2 Motion 19

Samacheer Kalvi 9th Science Guide Chapter 2 Motion

Question 7.
What do you infer if
(i) Distance – time graph is straight line.
(ii) Velocity time graph is curved.
(iii) Displacement time is zig zag.
Answer:
(i) Speed is constant.
(ii) Acceleration is not uniform.
(iii) Non uniform velocity.

Question 8.
Give the formula for each.
(i) Relation between initial, final velocity, acceleration and displacement in a uniformly accelerated straight line motion.
(ii) Relation between initial, final velocity, acceleration & time in a uniformly accelerated straight line motion.
(iii) Relation between initial velocity, acceleration, displacement and time.
Answer:
(i) Relation between initial, final Velocity, acceleration & displacement
in a uniformly accelerated straight line motion. v2 = u2 + 2as
(ii) Relation between initial, final velocity, acceleration & time
in a uniformly accelerated straight line motion. v = u + at
(iii) Relation between initial velocity, acceleration, displacement and time. s = ut+ 1/2 at2

Samacheer Kalvi 9th Science Guide Chapter 2 Motion

Question 9.
What is the difference between uniform acceleration and non – uniform acceleration?
Answer:
Uniform Acceleration

  1. It is the acceleration in which the object changes its velocity with equal intervals of time.
  2. eg. The motion of a ball rolling down.

Non – Uniform Acceleration

  1. It is the acceleration in which the object changes its velocity with unequal intervals of time.
  2. A car travels 2 km in 1st hour, 3 km in 2nd hour and 3.5 km in 3rd horn.

Question 11.
Define Acceleration.
Answer:
Acceleration is the rate of change of velocity with respect to time or it is the rate of change of velocity in unit time. It is a vector quantity. The SI unit of acceleration is

VI. Paragraph Questions :

Question 1.
Define acceleration and state its SI unit for motion along a straight line, when do we consider the acceleration to be (i) positive (ii) negative? Give an example of a body in uniform acceleration.
Answer:
Answer: Acceleration is the rate of change of velocity with respect to time or it is the rate of change of velocity in unit time. It is a vector quantity. The SI unit of acceleration is ms-2
Acceleration = Change in velocity/time
= (Final velocity – initial velocity)/time
a = \(\frac{v-u}{t}\)

If v > u, then ‘a’ is positive. If final velocity is greater than initial velocity, the velocity increase with time, the value of acceleration is positive.

If v < u, then a is negative. If final velocity is less than initial velocity
Example : The motion of a freely falling body and vertically thrown up body are the examples of uniform acceleration.
The motion of ball rolling down on an inclined plane is another example.

Samacheer Kalvi 9th Science Guide Chapter 2 Motion

Question 2.
Distinguish between uniform motion and non
Answer:
uniform motion.

  1. An object is said to be in uniform motion if it covers equkl distances in equal intervals of time.
  2. example of uniform motion ‘train’

non-uniform motion.

  1. If a body covers unequal distances in equal interval of time (or) equal distances in a different interval of time
  2. example of non – uniform motion ‘bus’

Question 3.
Define uniform circular motion and give an example of it. Why is it called accelerated motion?
Answer:
When an object is moving with a constant speed along a circular path, the change in velocity is only due to the change in direction. Hence it is accelerated motion. Example:

  1. The earth moves around the sun in a uniform circular motion.
  2. The moon moves in uniform circular motion around the earth.

Question 4.
When a body is said to be in (i) uniform acceleration (ii) non – uniform acceleration?
Answer:
(i) A body is said to be in uniform acceleration if it travels in a straight line and its velocity increases or decreases by equal amounts in equal time intervals.
(ii) A body is said to be in non-uniform acceleration if the rate of change of its velocity is not constant i.e. differs in different time intervals.

Samacheer Kalvi 9th Science Guide Chapter 2 Motion

Question 5.
What remains constant in uniform circular motion? And what changes continuously in uniform circular motion?
Answer:

  • Speed remains constant in a uniform circular motion.
  • Velocity changes continuously in a uniform circular motion.

Problems

Question 1.
A bus speed decreases from 50 km/h to 40 km/h in 3s, find the acceleration of the bus.
Answer:
Samacheer Kalvi 9th Science Guide Chapter 2 Motion 20

Question 2.
A car starting from rest moves with uniform acceleration of 0.2 ms-2 for 3 min. Fine the (a) speed acquired (b) the distance travelled.
Answer:
Initial speed (u) = 0 m/s
Acceleration (a) = 0.2 ms-2
Time taken (t) = 3 min = 3 × 60 = 180 s
Final velocity (v) = ?
Distance covered(s) = ?
v = u + at = 0 + 0.2 × 180 = 36 m/s
v = 36m/s
s = ut + 1/2 at2 = 0 + 1/2 × 0.2 × (180)2
= 0.1 × 32400 = 3240 m
s = 3240m

Samacheer Kalvi 9th Science Guide Chapter 2 Motion

Question 3.
A train is travelling at a speed of 90 kmh-1. Brakes are applied so as to produce a uniform acceleration of-0.5 ms-2, find how far the train will go before it is brought to rest.
Answer:
Initial velocity of train (u) = 90 km/h = \(\frac{90,000 \mathrm{~m}}{3,600 \mathrm{sec}}=25 \mathrm{~ms}^{-1}\)
Final velocity (v) = 0 ms-1
Acceleration (a) = – 0.5 ms-2
v2 = u2+ 2as
s = (v2 – u2) / 2a = (02 – 252) / -(2 × 0.5)
s = -625/-1 = 625m
s = 625m

Samacheer Kalvi 9th Science Guide Chapter 2 Motion

Question 4.
In a long-distance race the athletes were expected to take four rounds of the track such that the line of finish was same as the line of start. Suppose the length of the track was 300m,
Samacheer Kalvi 9th Science Guide Chapter 2 Motion 21
(i) What is the total distance to be covered by the athletes?
What is the total displacement of the athletes when they touch the finish line?
(iii) Is the motion of the athletes uniform or non- D .^starting point uniform?
(iv) Is the displacement & distance moved by an athlete at the end of the race equal?
Answer:
(i) Total distance covered = 4 × 300 = 1200 m
(ii) Displacement = 0 [final position – initial position]
(iii) Non – uniform.
∵ the direction of motion is changing while running on the track.
(iv) Both are not equal.

Question 5.
Ram swims in a 80m long swimming pool. He covers 160m in 1 min by swimming from one end to the other and back along the same straight pattern. Find the average speed and average velocity.
Answer:
Total distance = 160m
Total displacement = 0
Time taken (t) = 1 min = 60s
Samacheer Kalvi 9th Science Guide Chapter 2 Motion 22

Samacheer Kalvi 9th Science Guide Chapter 2 Motion

Question 6.
Abus from Chennai travels to Trichy passes loo km, 160 km at 10.15 am, 11.15 am respectively. Find the average speed of the bus during 10.15 – 11.15 am.
Answer:
The distance coveredbetween 10.l5am& 11.15 am = 160 – 100
= 60km
The time interval = 1 h
Average speed = 60/1
= 60km/h

Question 7.
In a distance-time graph of two objects A & B, which object is moving with greater speed when both are moving?
Answer:
Object B makes a longer angle with the time – axis. Its slope is greater than the slope of object A. Thus the speed of B is greater than that of A.
Samacheer Kalvi 9th Science Guide Chapter 2 Motion 23

Question 8.
Find the distance covered by a particle during the time interval which the speed-time graph is-shown in figure.
Answer:
Samacheer Kalvi 9th Science Guide Chapter 2 Motion 24
Distance covered in the. time interval 0 to 20s is equal to the area of the triangle OAB.
Area of A OAB. \(\frac { 1 }{ 2 }\) × base × height
\(\frac { 1 }{ 2 }\) × 20 x 20 = 200 ms-1

Samacheer Kalvi 9th Science Guide Chapter 2 Motion

Question 9.
A car moves 30 km in 30 min and the next 30 km in 40 min. Calculate the average speed for the entire journey.
Answer:
Answer:
Total time taken = 30 + 40 = 70 min. = \(\frac { 70 }{ 60 }\) hour
Total distance = 30 + 30 = 60 km
Samacheer Kalvi 9th Science Guide Chapter 2 Motion 25

Question 10.
A boy travels a distance of 3m due east and then 4m due north.
(a) How much is the total distance covered?
(b) What is the magnitude of the displacement?
Answer:
Samacheer Kalvi 9th Science Guide Chapter 2 Motion 26
(a) Total distance covered = 3 + 4 = 7m
(b) Net displacement: OB2 = OA2 + AB2
= 32 + 42
OB2 = 25m2
∴OB = 5m 0 3m
Net displacement = 5m

Samacheer Kalvi 9th Science Guide Chapter 2 Motion

Question 11.
During an experiment, a signal from a spaceship reached the ground station in five seconds. What was the distance of the spaceship from the ground station? The signal
travels at the speed of light that is 3 × 108 ms-1
Answer:
Time taken = 5 seconds.
Speed of signal u = 3 × 108 m/s ?
Distance = ?
Speed = Distance / Time
∴ Distance = Speed × Time
Distance = 3 × 108 × 5 = 15 × 108 m.

Question 12.
A train travelling at a speed of 90kmph. Brakes are applied so as to produce a uniform acceleration of -0.5 ms-2. Find how far the train will go before it is brought to rest?
Answer:
Here we have
Initial velocity , u = 90km/h
\(=\frac{90 \times 1000 \mathrm{~m}}{60 \times 60 \mathrm{~s}}=25 \mathrm{~m} / \mathrm{s}\)
Final velocity, v = 0
Acceleration, a = -0.5m/s2
Thus, distance travelled = ?
We know that, v2 = u2 + 2as
Samacheer Kalvi 9th Science Guide Chapter 2 Motion 27

Question 13.
The adjacent diagram shows the velocity-time graph of the body.
a) During what time interval is the motion of the body accelerated?
Answer:
At 0 to 4 second

Samacheer Kalvi 9th Science Guide Chapter 2 Motion

b) Find the acceleration in the time Interval mentioned in part ‘a’.
Answer:
\(\mathrm{a}=\frac{v-u}{t}=\frac{30-0}{4}=7.5 \mathrm{~m} / \mathrm{s}^{2}\)

c) What is the distance travelled by the body in the time interval mentioned ¡n part ‘a’?
Answer:Distance travelled Area under the graph
= Area of the triangle = 1/2 bh
= 1/2 × 4 × 30 = 60m

Question 14.
The following graph shows the motion of a car. What do you infer from the graph along with OA and AB? What is the speed of the car along with AB and what time it reached this speed?
a) What do you infer from the graph along OÄ and AB
Answer:
Graph along with OA: The car travels with uniform acceleration and uniform motion.
Graph along with AB : The car travels with constant speed and unaccelerated motion.
Samacheer Kalvi 9th Science Guide Chapter 2 Motion 28

b) What is the speed of the car along AB?
Answer:
Along AB : The speed of the car is constant.
From the graph, it seems the speed along AB is 72 km/hr.

c) What time it reached this speed
Answer:
It reaches this speed after 3.2 hours, that is, 3 hours, 12 minutes.

Samacheer Kalvi 9th Science Guide Chapter 2 Motion

Question 15.
From the following table, check the shape of the graph.
Samacheer Kalvi 9th Science Guide Chapter 2 Motion 29
Answer:
Samacheer Kalvi 9th Science Guide Chapter 2 Motion 30

Samacheer Kalvi 9th Science Guide Chapter 18 Organization of Tissues

Tamilnadu State Board New Syllabus Samacheer Kalvi 9th Science Guide Pdf Chapter 18 Organization of Tissues Text Book Back Questions and Answers, Notes.

Samacheer Kalvi 9th Science Solutions Chapter 18 Organization of Tissues

9th Science Guide Organization of Tissues Text Book Back Questions and Answers

I. Choose the correct answer:

Question 1.
The tissue composed of living thin walled polyhedral cell is
(a) parenchyma
(b) pollenchyma
(c) pclerenchyma
(d) none of above
Answer:
(d) none of above

 Samacheer Kalvi 9th Science Guide Chapter 18 Organization of Tissues

Question 2.
The fibres consists of
(a) parenchyma
(b) sclerenchyma
(c) collenchyma
(d) none of above
Answer:
(b) sclerenchyma

Question 3.
Companion cells are closely associated with
(a) sieve elements
(b) vessel elements
(c) trichomes
(d) guard cells
Answer:
(a) sieve elements

 Samacheer Kalvi 9th Science Guide Chapter 18 Organization of Tissues

Question 4.
Which of the following is a complex tissue?
(a) Parenchyma
(b) Collenchyma
(c) Xylem
(d) Sclerenchyma
Answer:
(c) Xylem

Question 5.
Aerenchyma is found in
(a) epiphytes
(b) hydrophytes
(c) halophytes
(d) xerophytes
Answer:
(b) hydrophytes

 Samacheer Kalvi 9th Science Guide Chapter 18 Organization of Tissues

Question 6.
Smooth muscles occur in
(a) uterus
(b) artery
(c) vein
(d) all of the above
Answer:
(d) all of the above

Question 7.
Nerve cell does not contains
(a) axon
(b) nerve endings
(e) tendons
(d) dendrités
Answer:
(c) tendons

 Samacheer Kalvi 9th Science Guide Chapter 18 Organization of Tissues

II. Match the following.

Question 1.

Sclereids Chlorenchyma
Chloroplast Sclerenchyma
Simple tissue Collenchyma
Companion cell Xylem
Tracheids Phloem

Answer:

Sclereids Sclerenchyma
Chloroplast Chlorenchyma
Simple tissue Collenchyma
Companion cell Phloem
Tracheids Xylem

III Fill in the blanks :

1. ……………. tissues provide mechanical support to organs.
Answer:
Compound epithelium

 Samacheer Kalvi 9th Science Guide Chapter 18 Organization of Tissues

2. Parenchyma, Collenchyma, Sclerenchyma are ……………. type of tissue.
Answer:
simple

3. ……………. and ……………… are complex issues.
Answer:
Xylem, phloem

4. Epithelial cells with cilia are fóund in ……………….. of our body
Answer:
trachea or windpipe

 Samacheer Kalvi 9th Science Guide Chapter 18 Organization of Tissues

5. Lining of the small intestine is made up of …………………..
Answer:
columnar epithelium

IV. State whether true or false. If false, correct the statement :

1. Epithelial tissue is protective tissue in an animal body.
Answer:
True.

2. Bone and cartilage are two types of areolar connective tissue.
Answer:
False.
Correct statement: Bone and cartilage are two types of supportive connective tissue.

3. Parenchyma is a simple tissue.
Answer:
True.

 Samacheer Kalvi 9th Science Guide Chapter 18 Organization of Tissues

4. Phloem is made up of tracheids.
Answer:
False.
Correct statement: Phloem is made up of sieve tubes.

5. Vessels are found in collenchyma.
Answer:
False.
Correct statement: Vessels are found in the xylem.

 Samacheer Kalvi 9th Science Guide Chapter 18 Organization of Tissues

V. Answer briefly :

Question 1.
What are intercalary meristems? How do they differ from other meristems?
Answer:
Intercalary meristem lies between the region of permanent tissues and is part of primary meristem which is detached due to formation of intermittent permanent tissues. It is found either at the base of leaf e.g. Pinus or at the base of intemodes e.g. grasses.

Question 2.
What is complex tissue? Name the various kinds of complex tissues.
Answer:

  • Complex tissues are made of more than one type of cells that work together as a unit.
  • Complex tissues consist of parenchyma and sclerenchyma cells. However, collenchymatous cells are not present in such tissues.
  • Common examples are xylem and phloem.

 Samacheer Kalvi 9th Science Guide Chapter 18 Organization of Tissues

Question 3,.
Mention the most abundant muscular tissue found in our body. State its function.
Answer:
Connective tissue is the most abundant and widely distributed tissue. It provides a structural framework and gives support to different tissues forming organs.

Question 4.
What is skeletal connective tissue? How is it helpful in the functioning of our body?
Answer:
The supporting or skeletal connective tissues forms the endoskeleton of the vertebrate body. They protect various organs and help in locomotion. The supportive tissues include cartilage and bone.

 Samacheer Kalvi 9th Science Guide Chapter 18 Organization of Tissues

Question 5.
Why should gametes be produced by meiosis during sexual reproduction?
Answer:
Meiosis is important as it produces gametes i.e., male or female germ cells. During meiosis, a germ cell or gamete divides to make four new sex cells. As a result of fertilization two gamates join together to form an egg or zygote. Therefore only if gametes are produced, fertilization can take place.

Question 6.
In which stage of mitosis the chromosomes align in an equatorial plate? How?
Answer:
Metaphase (meta – after) The duplicated chromosomes arrange on the equatorial plane and form the metaphase plate. Each chromosome gets attached to a spindle fibre by its centromere. The centromere of each chromosome divides into two each being associated with a chromatid.

 Samacheer Kalvi 9th Science Guide Chapter 18 Organization of Tissues

VI. Answer in detail:

Question 1.
What are the permanent tissues? Describe the different types of simple permanent tissues.
Answer:
Permanent tissues:
Permanent tissues are those in which, growth has stopped either completely or for the time being. At times, they become meristematic partially or wholly.

Different types of simple permanent tissue :
Simple tissue: Simple tissue is homogeneous-composed of structurally and functionally similar cells. Eg : Parenchyma, collenchyma, and sclerenchyma.

Parenchyma:

Samacheer Kalvi 9th Science Guide Chapter 18 Organization of Tissues 1

  • Parenchyma are simple permanent tissue composed of living cells.
  • Parenchyma cells are thin-walled, oval, rounded, or polygonal in shape with well-developed spaces among them.
  • In aquatic plants, parenchyma possesses intercellular air spaces and is named as aerenchyma.
  • When exposed to light, parenchyma cells may develop chloroplasts and are known as chlorenchyma.

Functions:

  • Parenchyma may store water in many succulent and xerophytic plants.
  • It also serves the functions of storage of food reserves, absorption, buoyancy, secretion, etc

Collenchyma:
Samacheer Kalvi 9th Science Guide Chapter 18 Organization of Tissues 2

  • Collenchyma is a living tissue found beneath the epidermis.
  • Cells are elongated with unevenly thickened non-lignified walls. Cells have rectangular oblique or tapering ends and persistent protoplast.
  • They possess thick primary non-lignified walls.
    Functions: They provide mechanical support for growing organs.

Sclerenchymà:

  • Scierenchyma consists of thick-walled cells which are often lignified.
  • Scierenchyma cells do not possess living protoplasts at maturity. Scierenchyma cells are grouped into

(i) fibers and (ii) sclereids.
Samacheer Kalvi 9th Science Guide Chapter 18 Organization of Tissues 3

Fibres : Elongated scierenchymatous cells, usually with pointed ends. Their walls are lignified. Fibres are abundantly found in many plants. Eg. Jute.
Sclereids:

  • Sclereids are widely distributed in plant body. They are usually broad, may occur in single or in groups.
  • Sclereids are isodiametric, with lignified walls. Pits are prominent and seen along the walls.
  • Lumen is filled with wall materials. Sclereids are also common in fruits and seeds.

 Samacheer Kalvi 9th Science Guide Chapter 18 Organization of Tissues

Question 2.
Write about the elements of Xylem.
Answer:
Xylem is a conducting tissue which conducts water, mineral nutrients upward from root to leaves. Xylem is also meant for mechanical support to the plant body. Xylem is composed of different kinds of elements. They are

  1. xylem tracheids
  2. xylem fibres
  3. xylem vessels and
  4. xylem parenchyma.

(i) Xylem tracheids: They are elongated or tube-like dead cells with hard, thick and lignified walls. Their ends are tapering, blunt or chisel-like. These cells are devoid of protoplast. They have large lumen without any content. Their function is conduction of water and providing mechanical support to the plant.

(ii) Xylem fibers: These cells are elongated, lignified and pointed at both the ends. Xylem fibres help in the conduction of water and nutrients from root to the leaf and also provide mechanical support to the plant.

(iii) Xylem vessels: They are long cylindrical, tube-like structures with lignified walls and wide central lumen. These cells are dead as these do not have protoplast. They are arranged in longitudinal series in which the partitioned walls (transverse walls) are perforated, and so the entire structure looks-like a water pipe. Their main function is the transport of water and minerals from root to leaf, and also to provide mechanical strength.

(iv) Xylem parenchyma: Its cells are living and thin-walled. The main function of xylem parenchyma is to store starch and fatty substances.

Question 3.
List out the differences< between mitosis and meipsis.
Answer:

Mitosis Meiosis
1. Occurs in somatic cells. Occurs in reproductive cells
2. Involved in growth and occurs continuously throughout life. Involved in gamete formation only during the reproductively active age.
3. Consists of single division. Consists of two divisions.
4. Two diploid daughter cells are formed. Four haploid daughter cells are formed.
5. The chromosome number in the daughter cell is similar to the parent cell (2n). The chromosome number in the daughter cell is just half (n) of the parent cell.
6. Identical daughter cells are formed. Daughter cells are not similar to the parent cell and are randomly assorted.

 Samacheer Kalvi 9th Science Guide Chapter 18 Organization of Tissues

VII. Higher Order Thinking Skills :

Question 1.
What is the consequence that occurs if all blood platelets are removed from the blood?
Answer:
Blood platelets play a major role in the clotting of blood whenever there is a wound/injury. If blood platelets are removed from the blood, clotting of blood will not occur. In case of any injury/surgery etc., blood will be lost from the body in excess and may even prove to be fatal.

2. Which are not true cells in the blood? Why?
Answer:
Red blood cells or erythrocytes cannot be considered as true cells since they have a nucleus only in the early stages. A mature RBC lacks a nucleus which is the controlling centre of all living cells.

Intext Activities

ACTIVITY – 1
Rinse your mouth with water. Using a toothpick or ice-cream stick, scrap superficial cells from the inner side of the cheek and spread it on a clean glass slide. Dry the glass slide with the scrap cells taken from the inner side of the cheek. Add two drops of methylene blue stain. Identify the cells under low and high power of the microscope.
Solution:
1. Large irregularly shaped cells with cell walls.
2. Dark blue nucleus at the central part of each cell.
3. Lightly stained cytoplasm colour in each cell.

9th Science Guide Organization of Tissues Additional Important Questions and Answers

I. Choose the correct answer :

Question 1.
A meristematic tissue consists of
(a) immature cells that are capable of undergoing cell division.
(b) mature cells
(c) non-living cells
(d) sclerenchyma cells
Answer:
(a) immature cells that are capable of undergoing cell division

Question 2.
Two long bones of the hand are dislocated in a person who met with an accident. Which among the following may be the possible reason?
(a) Tendon injury
(b) Break of skeletal muscle
‘(c) Ligament tear
(d) Rupture of Areolar tissue
Answer:
(c) Ligament tear

 Samacheer Kalvi 9th Science Guide Chapter 18 Organization of Tissues

Question 3.
Non-striated muscles are found in
(a) blood vessels
(b) gastric glands
(c) urinary bladder
(d) all of these
Answer:
(d) all of these

Question 4.
Which of the following is not found in a neuron?
(a) Sarcolemma
(b) Dendrite
(c) Myelin sheath
(d) Axon
Answer:
(a) Sarcolemma

Question 5.
Cylindrical, unbranched multinucleated cells are
(a) striated muscle cells
(b) smooth muscles
(c) cardiac muscles
(d) none of the above.
Answer:
(a) striated muscle cells

 Samacheer Kalvi 9th Science Guide Chapter 18 Organization of Tissues

Question 6.
The matrix of the bone is rich in
(a) elastin
(b) reticular fibres
(c) collagen
(d) myosin
Answer:
(c) collagen

Question 7.
Which muscles act involuntarily?
(i) Striated muscles
(ii) Smooth muscles
(iii) Cardiac muscles
(iv) Skeletal muscles
(a) (i) and (ii)
(b) (ii) and (iii)
(c) (iii) and (iv)
(d)(i) and (iv)
Answer:
(b) (ii) and (iii)

Question 8.
Tendon connects
(a) cartilage with muscles
(b) bone with skeletal muscles
(c) ligament with muscles
(d) bone with bone
Answer:
(b) bone with skeletal muscles

 Samacheer Kalvi 9th Science Guide Chapter 18 Organization of Tissues

Question 9.
In a certain type of cell division, the diploid number of chromosomes is reduced to half. This kind of division occurs in
(a) testis
(b) ovary
(c) both ovary and testis
(d) all body cells
Answer:
(c) both ovary and testis

Question 10.
……………… is derived from the ground meristem.
(a) Cortex
(b) Epidermis
(c) Xylem
(d) Cambium
Answer:
(a) Cortex

Question 11.
The function of phloem fibres is …………….to the plant body
(a) passage of food
(b) Store food
(c) mechanical strength
(d) preparation of food
Answer:
(c) mechanical strength

 Samacheer Kalvi 9th Science Guide Chapter 18 Organization of Tissues

Question 12.
The …………….. epithelium is also known as pavement membrane.
(a) Ciliated
(b) Squamous
(c) Cuboidal
(d) Glandular
Answer:
(b) Squamous

Question 13.
Elastic structures that connect bones to bones are called ………………..
(a) muscles
(b) tendons
(c) ligaments
(d) areolar tissue
Answer:
(c) ligaments

 Samacheer Kalvi 9th Science Guide Chapter 18 Organization of Tissues

Question 14.
………………… is seen in unicellular animals.
(a) Mitosis
(b) meiosis
(e) Amitosis
(d) none of the above
Answer:
(c) Amitosis

Question 15.
The disappearance of spindle fibres is seen in …………….
(a) metaphase
(b) prophase
(c) anaphase
(d) telophase
Answer:
(d) telophase

Question 16.
The ………………… is a single, long fiber like process that develops from the cyton.
(a) dendron
(b) axon
(c) dendrite
(d) neurilemma
Answer:
(b) axon

 Samacheer Kalvi 9th Science Guide Chapter 18 Organization of Tissues

Question 17.
Bouquet stage refers to ……………..
(a) diakinesis
(b) leptotene
(c) zygotene
(d) pachytene
Answer:
(b) leptotene

Fill in the blanks :

1. The ……………. tissues are made up of more than one type of cells and these woks together as a unit.
Answer:
complex

2. The two types of skeletal connective tissues are ……………. and …………….
Answer:
bone, cartilage

3. Humans have 46 chromosomes. Their sperms and eggs will have ……………. chromosomes each.
Answer:
23

 Samacheer Kalvi 9th Science Guide Chapter 18 Organization of Tissues

4. During pairing of chromosomes in meiosis, the …………….. chromosomes come to lie side by side.
Answer:
homologous

5. The word meristem is derived from a Greek word ………………
Answer:
Meristos

6. Cork cambium is an example of ……………… meristem.
Answer:
secondary

 Samacheer Kalvi 9th Science Guide Chapter 18 Organization of Tissues

7. The meristem found at the base of intemodes is called ……………….
Answer:
intercalary meristem

8. In apple, paranchyma stores ………………
Answer:
sugar

9. Fibres are extensively longer ranging from 20 mm to 550 mm ……………….
Answer:
corchorus capsularis (jute)

10. During mieosis in pachytene, stages the paired chromosomes are called ………………….
Answer:
bivalents

 Samacheer Kalvi 9th Science Guide Chapter 18 Organization of Tissues

11. Mitosis was discovered by …………………..
Answer:
Flemming

12. Both smooth and cardiac muscles are …………….. in nature.
Answer:
involuntary

13. ………………. is a non-flexible skeletal connective tissue.
Answer:
Bone

 Samacheer Kalvi 9th Science Guide Chapter 18 Organization of Tissues

14. ……………. acts as a fat reservoir.
Answer:
Adipose tissue

15. …………….. epithelium is seen in sweat glands.
Answer:
Cuboidal

16. Genetic variations occur in meiosis because of …………….
Answer:
crossing over

III. State whether True or false. If false, write the correct statement:

1. Epithelial layer does not allow regulation of materials between the body and the external environment.
Answer:
False.
Correct statement: Epithelium is involved in the absorption and elimination of waste.

2. Striated and non-striated tissues are types of epithelial tissues.
Answer:
False.
Correct statement: They are types of muscular tissues.

 Samacheer Kalvi 9th Science Guide Chapter 18 Organization of Tissues

3. Spindle formation occur in amitosis.
Answer:
False.
Correct statement: Spindle formation occur in mitosis.

4. Movement of food in the alimentary canal is because of cardiac muscles.
Answer:
False.
Correct statement: Movement of food is alimentary canal by the rhythmic con t no-tom and relaxation of the muscular nails of the alimentary canal.
Correct statement: Movement of food in the alimentary canal.

5. A mature RBC lacks a nucleus.
Answer:
True

6. Excessive pulling of bones causes a sprain.
Answer:
False.
Correct statement: Sprain is caused by excessive pulling of ligaments.

 Samacheer Kalvi 9th Science Guide Chapter 18 Organization of Tissues

7. Glandular epithelium gives a stratified appearance.
Answer:
False.
Correct statement: Compound epithelium given a stratified appearance.

8. Sieve cells have no companion cells.
Answer:
True.

9. Conduction can be bidirectional in phloem tissue.
Answer:
True.

10. White blood corpuscles contain respiratory pigment hemoglobin.
Answer:
False.
Correct statement: Red blood corpuscles contain respiratory pigment hemoglobin.

 Samacheer Kalvi 9th Science Guide Chapter 18 Organization of Tissues

IV. Assertion and Reason type:

Direction: In each of the following questions, a statement of Assertion is given and a corresponding statement of Reason is given just below it. Of statements, given below, mark the correct answer as
(a) Both Assertion and Reason are true and Reason is the correct explanation of Assertion.
(b) Both Assertion and Reason are true that Reason is not the correct explanation of Assertion.
(c) Assertion is true but Reason is false.
(d) Both Assertion and Reason are false.

Question 1.
Assertion: Non-striated muscles are said to be voluntary in nature.
Reason: Non-striated muscles are under the control of our will.
Answer:
(d) Both Assertion and Reason are false

Question 2.
Assertion: Materials are exchanged between epithelial and connective tissues by diffusion.
Reason: Blood vessels are absent in epithelial tissue.
Answer:
(a) Assertion and Reason are true and Reason is the correct explanation of Assertion

 Samacheer Kalvi 9th Science Guide Chapter 18 Organization of Tissues

V. Answer in one or two sentences :

Question 1.
Name the two types of sclerenchyma cells.
Answer:
Sclerenchyma cells are grouped into

  1. fibres and
  2. sclereids.

Question 2.
Name the components of xylem and phloem.
Answer:
Xylem is composed of :

  • Xylem tracheids
  • Xylem fibres
  • Xylem vessels
  • Xylem parenchyma

Phloem is composed of:

  • Sieve elements
  • Companion cells
  • Phloem fibres
  • Phloem parenchyma

Question 3.
Name the tissue that connects muscle to bone in humans.
Answer:
Tendons join skeletal muscles to bones in our body.

 Samacheer Kalvi 9th Science Guide Chapter 18 Organization of Tissues

Question 4.
Name the tissue that stores excess fat in our body.
Answer:
Adipose tissue.

Question 5.
Name the connective tissue with a fluid matrix.
Answer:
Blood and lymph

Question 6.
Name the tissue present in the brain.
Answer:
Nervous tissue.

Question 7.
What is plate meristem?
Answer:
These cells divide into two planes resulting in an increase in the area of an organ.
Eg: Leaf formation.

 Samacheer Kalvi 9th Science Guide Chapter 18 Organization of Tissues

Question 8.
Differentiate collenchyma and sclerenchyma.
Answer:

Collenchyma Sclerenchyma
It consists of living cells It consists of dead cells
Cells contain protoplasm Cells do not possess living protoplast
Cell walls are non-lignified Cell walls are lignified

Question 9.
Mention the type of epithelium seen in alveoli of lungs.,
Answer:
Squamous epithelium.

Question 10.
Name the supportive connective tissues.
Answer:
Cartilage and bone

Question 11.
Name the cartilage cells present in the matrix.
Answer:
Chondrocytes.

 Samacheer Kalvi 9th Science Guide Chapter 18 Organization of Tissues

Question 12.
What is the role of RBC?
Answer:
RBC contains a respiratory pigment called hemoglobin which is involved in the transport of oxygen to tissues.

Question 13.
Mention the stages of meiotic Prophase -I.
Answer:
Leptotene, Zygotene, Pachytene, Diplotene, Diakinesis.

Question 14.
What is the significance of Meiosis?
Answer:
The constant number of chromosomes in a given species is maintained by meiotic division.

 Samacheer Kalvi 9th Science Guide Chapter 18 Organization of Tissues

Question 15.
Draw a shoot apex and label the meristem’s parts.
Answer:
Samacheer Kalvi 9th Science Guide Chapter 18 Organization of Tissues 4

VI. Short Answer Type :

Question 1.
How would you differentiate meristematic and permanent tissue?
Answer:

Meristematic tissue Permanent tissue
Cytoplasm is dense, and vacuoles are nearly absent. Usually large central vacuole present in living permanent cells.
Intercellular spaces absent. Intercellular spaces present.
Component cells are small, spherical or polygonal and undifferentiated. Component cells are large, differentiated with different shapes.
Cell wall is thin and elastic. Cell wall is thick.
Nucleus is large and prominent. Nucleus is less conspicuous.
Cells grow and divide regularly. Cells do not normally divide.
Provides mechanical support and elasticity to the plant body. Provides only mechanical support.

Question 2.
Differentiate fibres from sclereids.
Answer:

Sclereids Fibres
Usually broad Elongated narrow thread-like
End walls blunt Usually with pointed ends.
Occur singly Occur in bundles
Deep pits Narrow pits

 Samacheer Kalvi 9th Science Guide Chapter 18 Organization of Tissues

Question 3.
Which tissue is the main component of tendons and ligaments? How do they differ in function?
Answer:
Dense Connective Tissue is a fibrous connective tissue densely packed with fibres and fibroblasts. It is the principal component of tendons and ligaments.

a. Tendons: Cord-like, strong, structures that join skeletal muscles to bones. Tendons have great strength and limited flexibility. They consist of parallel bundles of collagen fibres, between which are present rows of fibroblasts.

b. Ligaments: They are highly elastic structures and have great strength which connects bones to bones. They contain very little matrix. They strengthen the joints and allow normal movement.

Question 4.
What are the fibres present in the connective tissue proper?
Answer:
Connective tissue proper: Connective tissue proper consists of collagen fibres, elastin fibres and fibroblast cells.

Areolar tissue: It has cells and fibres loosely arranged in a semi-fluid ground substance called matrix. It takes the form of fine threads crossing each other in every direction leaving small spaces called areolae. It joins skin to muscles, fills space inside organs and is found around muscles, blood vessels and nerves. It helps in repair of tissues after injury and fixes skin to underlying muscles.

Adipose Tissue: Adipose tissue is the aggregation of fat cells or adipocytes spherical or oval in shape. It serves as fat reservoir. The matrix consists of collagen fibres, elastin fibres and fibroblast cells.

 Samacheer Kalvi 9th Science Guide Chapter 18 Organization of Tissues

Question 5.
How are collagen fibres organized in dense connective tissues?
Answer:

  • Dense connective tissue is a fibrous connective tissue densely packed with fibres and fibroblasts. It is the principal component of tendon and ligaments.
  • Tendons consist of parallel bundles of collagen fibres, between which are present rows of fibroblasts.
  • Ligaments are highly elastic structures and contain very little matrix.

Question 6.
Write one point of difference between
a) Bone and cartilage.
b) Simple and compound epithelial tissue.
Answer:
a)

Bone Cartilage
It is solid, rigid, and strong, non-flexible skeletal connective tissue. It is a soft, semi-rigid, flexible skeletal connective tissue.
The matrix of the bone is in the form of concentric rings called lamellae The matrix is composed of large cartilage cells called chondrocytes

b)

Simple epithelium tissue Çompound epithelium tissue
It is composed of a single layer of cells
resting ón a basement membrane.
It is composed of several layers of cells.
Only the cells of the deepest layer rest
on the basement membrane.

Question 7.
Why is blood considered to be a fluid connective tissue?
Answer:

  • The blood and the lymph are the fluid connective tissues which link different parts of the body. The cells of the connective tissue are loosely spaced and are embedded in an intercellular matrix.
  • Blood contains corpuscles which are red blood cells (erythrocytes), white blood cells (leucocytes), and platelets. In this fluid connective tissue, blood cells move in a fluid matrix called plasma. The plasma contains inorganic salts and organic substances. It is a main circulating fluid that helps in the transport of nutrient substances.

 Samacheer Kalvi 9th Science Guide Chapter 18 Organization of Tissues

Question 8.
Give the sequence of the events occurring during prophase of mitosis.
Answer:

  • During this stage, chromosomes become short and thick and are clearly visible inside the nucleus.
  • Centrosome splits into two daughter centrioles and occupies opposite poles of the cell.
  • Each centriole is surrounded by aster rays. Spindle fibres appear between the two centrioles.
  • The nuclear membrane and nucleolus disappear gradually.

Question 9.
Why is meiosis called reductional division and mitosis as equational division?
Answer:

  • In mitosis one parent cell divides into two identical daughter cells, each with a nucleus having the same amount of DNA, same number of chromosomes and genes as the parent cells. It is therefore called an equational division.
  • Meiosis is called reduction division because the chromosome number is reduced to haploid (n) from diploid (2n) in the daughter cells.

Question 10.
What is terminalization?
Answer:
In the stage of diplotene of meiotic prophase I, chiasmata begin to move along the length of the chromosome from the centromere towards the end resulting in terminalization.

 Samacheer Kalvi 9th Science Guide Chapter 18 Organization of Tissues

Question 11.
What is a tetrad?
Answer:
The chromosomes are visible as long paired twisted threads. The pairs so formed are called bivalents. Each bivalent now contains four chromatids (tetrad stage) in pachytene of mieotic prophase I. The condition of bivalent containing four chromatids are called tetrad stage.

Question 12.
What is crossing over?
During pachytene of mieotic prophase I, the chromatids break and the broken segments are interchanged between homologous chromosomes. The points of exchange are the chiasmata. This is called .crossing over.

Question 13.
What is bouquet stage?
Answer:
During leptotene of mieotic prophase I, the chromosomes become uncoiled and assume long thread-like structures and take up a specific orientation inside the nucleus. They form a bouquet stage.

 Samacheer Kalvi 9th Science Guide Chapter 18 Organization of Tissues

Question 14.
What is zygotene?
Answer:
It is one of the stages of mieoticphophase I. Two homologous chromosomes approach each other and begin to pair. The pairing of homologous chromosomes is called synapsis.

Question 15.
Explain amitosis.
Answer:
It is the simplest model of cell division and occurs in unicellular animals, aging cells and in foetal membranes. During amitosis, the nucleus elongates first, and a constriction appears in it which deepens and divides the nucleus into two, followed by this cytoplasm divides resulting in the formation of two daughter cells.

Question 16.
Write the salient features of the compound epithelium.
Answer:

  • It consists of more than one layer of cells and gives a stratified appearance. Hence, they are also known as stratified epithelial cells.
  • The main function of this epithelium is to give protection to the underlying tissues against mechanical and chemical stress.
  • They also cover the dry surface of the skin, the moist surface of the buccal cavity, and the pharynx.

 Samacheer Kalvi 9th Science Guide Chapter 18 Organization of Tissues

Question 17.
Write a note the significance of mitosis.
Answer:

  • This equational division results in the production of diploid daughter cells (2n) with equal distribution of genetic material (DNA).
  • In multicellular organisms growth, organ development and an increase in body size are accomplished through the process of mitosis.
  • Mitosis helps in the repair of damaged and wounded tissues by the renewal of the lost cells.

Question 18.
Draw a neuron and label the parts.
Answer:
Samacheer Kalvi 9th Science Guide Chapter 18 Organization of Tissues 5

VII. Answer in detail:

Question 1.
What are meristems? Describe the distribution and functions of various types of meristems.
Answer:
Meristematic tissues are group of immature cells that are capable of undergoing cell division. In plants, the meristem is found in zones where growth can take place. Example: apex of stem, root, leaf primordia, vascular cambium, cork cambium, etc.,

Types of Meristems based on position:
On the basis of their position in the plant, meristems are of three types: Apical meristem, Intercalary meristem, and Lateral meristem.

Apical meristem: These are found at the apices or growing points of root and shoot and bring about an increase in length.

Intercalary meristem: It lies between the region of permanent tissues and is part of the primary meristem. It is found either at the base of leaf e.g. pinus or at the base of internodes e.g. grasses.

Lateral Meristem: These are arranged parallel and causes the thickness of the plant part.

Functions: Meristems are actively dividing tissues of the plant, that are responsible for primary (elongation) and secondary (thickness) growth of the plant.
Samacheer Kalvi 9th Science Guide Chapter 18 Organization of Tissues 6

Question 2.
Give one reason for the following:
a. Blood is fluid connective tissue.
b. Skeletal muscles are voluntary muscles.
c. Heart muscles are involuntary in nature.
Answer:
The blood and the lymph are the fluid connective tissues which link different parts of the body. The cells of the connective tissue are loosely spaced and are embedded in an intercellular matrix.

(a) Blood: Blood contains corpuscles which are red blood cells (erythrocytes), white blood cells (leucocytes), and platelets. In this fluid connective tissue, blood cells move in a fluid matrix called plasma. The plasma contains inorganic salts and
organic substances. It is a main circulating fluid that helps in the transport of nutrient substances.

(b) They work under our control and are also known as voluntary muscles. They are not under the control of our will and so are called involuntary muscles.

(c) Cardiac muscle: It is a special contractile tissue present in the heart. The muscle fibers are cylindrical, branched, and uninucleate The branches join to form a network called as itercalated disc which are unique distinguishing features of the
cardiac muscles. The contraction of cardiac muscle is involuntary and rhythmic.

 Samacheer Kalvi 9th Science Guide Chapter 18 Organization of Tissues

Question 3.
Explain simple epithelium and its types.
Answer:
Simple Epithelium :
1. It is formed of a single layer of cells. It forms a lining for the body cavities and ducts.
2. Simple epithelium is further divided into the following types.

  • Squamous epithelium
  • Cuboidal epithelium
  • Columnar epithelium
  • Ciliated epithelium
  • Glandular epithelium

(i) Squamous epithelium :

  • It is made up of thin, flat cells with prominent nuclei. These cells have irregular boundaries and bind with neighbouring cells.
  • The squamous epithelium is also known as pavement membrane, which forms the delicate lining of the buccal cavity, alveoli of lungs, proximal tubule of kidneys, blood vessels etc.
  • It protects the body from mechanical injury, drying and invasion of germs.
    Samacheer Kalvi 9th Science Guide Chapter 18 Organization of Tissues 7

(ii) Cuboidal epithelium:

  • It is composed of single layer of cubical cells.
  • The nucleus is round and lies in the centre.
  • This tissue is present in the thyroid vesicles, salivary glands, sweat glands, exocrine pancreas.
  • It is also found in the intestine and tubular part of the nephron (kidney tubules) as microvilli that increase the absorptive surface area.
  • Their main function is secretion and absorption.
    Samacheer Kalvi 9th Science Guide Chapter 18 Organization of Tissues 8

(iii) Columnar epithelium:

  • It is composed of a single layer of slender, elongated and pillar like cells.
  • Their nuclei are located at the base.
  • It is found lining the stomach, gall bladder, bile duct, small intestine, colon, oviducts and forms a mucous membrane. ‘
  • They are mainly involved in secretion and absorption.
    Samacheer Kalvi 9th Science Guide Chapter 18 Organization of Tissues 9

(iv) Ciliated epithelium :

  • Certain columnar cells bear numerous delicate hair like out growths called ilia and are called ciliated epithelium.
  • Their function is to move particles or mucus in a specific direction over the epithelium.
  • It is seen in the trachea of wind-pipe, bronchioles of respiratory tract, kidney tubules and fallopian tubes of oviducts.
    Samacheer Kalvi 9th Science Guide Chapter 18 Organization of Tissues 10

(v) Glandular epithelium :

  • Epithelial cells are often modified to form specialized gland cells which secrete chemical substances at the epithelial surface.
  • This lines the gastric glands, pancreatic tubules and intestinal glands.
    Samacheer Kalvi 9th Science Guide Chapter 18 Organization of Tissues 11

Question 4.
Explain the components of phloem tissue.
Answer:
Phloem is a complex tissue and consists of the following elements :
(i) Sieve elements
(ii) Companion cells
(iii) Phloem fibres
(iv) Phloem parenchyma

(i) Sieve elements :

  • The conducting elements of phloem are collectively called as Sieve elements.
  • Sieve tubes are elongated, tube-like slender cells placed end to end. The transverse walls at the ends are perforated and are known as sieve plates.
  • The main function of sieve tubes is translocation of food, from leaves to the storage organs of the plants.

(ii) Companion cells : These are elongated cells attached to the lateral wall of the sieve tubes. A companion cell may be equal in length to the accompanying sieve tube element or the mother cell may be divided transversely forming a series of companion cells.

(iii) Phloem parenchyma : The phloem parenchyma are living cells which have cytoplasm and nucleus. Their function is to store food materials.

(iv) Phloem fibers : Sclerenchymatous cells associated with primary and secondary phloem are commonly called phloem fibers. These cells are elongated, lignified and provide mechanical strength to the plant body.

 Samacheer Kalvi 9th Science Guide Chapter 18 Organization of Tissues

Question 5.
Write a note on blood and its components.
Answer:
Blood is a fluid connective tissue.
Blood contains corpuscles which are red blood cells (erythrocytes), white blood cells (leucocytes) and platelets. In this fluid connective tissue, the blood cells move in a fluid matrix called. The plasma contains inorganic salts and organic substances. It is a main circulating fluid that helps in the transport of nutrient substances.

Red blood corpuscles (Erythrocytes):

  • The red blood corpuscles are oval shaped, circular, biconcave disc-like and lack nucleus when mature (mammalian RBC).
  • They contain a respiratory pigment called haemoglobin which is involved in the transport of oxygen to tissues.

White blood corpuscles (Leucocytes): They are larger in size, contain distinct nucleus and are colourless. They are capable of amoeboid movement and play an important ‘ role in body’s defense mechanism. WBC’s are of two types :
(i) Granulocytes.
(ii) Agranulocytes.

(i) Granulocytes have irregular shaped nuclei and cytoplasmic granules. They include the neutrophils, basophils and eosinophils. Agranulocytes lack cytoplasmic granules and include the lymphocytes and monocytes.

Blood platelets : They are minute, anucleated, fragile fragments of giant bone marrow called mega karyocytes They play an important role in blood clotting mechanism.
Samacheer Kalvi 9th Science Guide Chapter 18 Organization of Tissues 12

VIII. Higher Order Thinking Skills :

Question 1.
Identify the figure given below
Samacheer Kalvi 9th Science Guide Chapter 18 Organization of Tissues 13
(a) Label the parts A, B and C.
(b) What is the chemical composition of the tissue?
Answer:
(a) T.S. of Bone
(A) Lamellae
(B) Lacunae
(C) Central (Haversian canal)
(b) The matrix of the bone is rich in calcium salts and collagen fibres which gives the bone its strength.
(c) C – Haversian canal

 Samacheer Kalvi 9th Science Guide Chapter 18 Organization of Tissues

Question 2.
Identify figures A and B.
Samacheer Kalvi 9th Science Guide Chapter 18 Organization of Tissues 14
(a) …………… epithelium forms the outer lining of the buccal cavity.
(b) ………………. epithelium consist of ceils that are tall and pillar-like.
(c) Which one allows diffusion of substances?
(d) Which is called pavement epithelium?
(e) Which epithelium lines the gastrointestinal tract and epiglottis?
Answer:
Figure A – Squamous Epithelium
Figure B. – Glandular epithelium
(a) Squamous
(b) Columnar
(c) Columnar epithelium
(d) Squamous epithelium
(e) Columnar epithelium

Question 3.
If cell (A) has undergone one mitotic division and another cell (B) has completed its meiotic division. The number of cells produced in A and B would be
Cell A: Cell B :
Answer:
Cell A : 2 daughter cells.
Cell B : 4 daughter cells.

Question 4.
Identify the stage of mitosis from the below picture. List the chromosomal events in this stage.
Samacheer Kalvi 9th Science Guide Chapter 18 Organization of Tissues 15

Answer:
Mitotic anaphase
(i) The centromeres attaching the two chromatids divide and the two daughter chromatids of each chromosome separate and migrate towards the two opposite poles.
(ii) The migration of the daughter chromosomes is achieved by the contraction of spindle fibres.

 Samacheer Kalvi 9th Science Guide Chapter 18 Organization of Tissues

Question 5.
Identify the following relationship
Cuboidal : Epithelial
Cardiac : ………..
Granulocytes : …………
Osteocytes : ………….
Answer:
Cardiac : Muscular
Granulocytes : Blood cells
Osteocytes : Bone cells

Question 6.
Umbilical cord blood is collected at the time of child birth and stored in stem cell banks? Reason out.
Answer:

  • Umbilical cord blood consists of stem cells, they are undifferentiated cells which undergo unlimited divisions and give rise to one or more different types of cells. – Embryonic stem cells differentiate into different tissues and organs.
  • Stem cells can be used in the treatment of certain degenerative diseases in future.

Question 7.
How do WBC help in defence?
Answer:
They are capable of amoeboid movement and play an important role. They engulf or destroy foreign bodies.

Samacheer Kalvi 9th Science Guide Chapter 17 Animal Kingdom

Tamilnadu State Board New Syllabus Samacheer Kalvi 9th Science Guide Pdf Chapter 17 Animal Kingdom Text Book Back Questions and Answers, Notes.

Samacheer Kalvi 9th Science Solutions Chapter 17 Animal Kingdom

9th Science Guide Animal Kingdom Text Book Back Questions and Answers

I. Choose the correct answer :

Question 1.
Find the group having only marine members.
(a) Mollusca
(b) Coelenterata
(c) Echinodermata
(d) Porifera
Answer :
(d) Echinodermata

 Samacheer Kalvi 9th Science Guide Chapter 17 Animal Kingdom

Question 2.
Mesoglea is present in
(a) Porifera
(b) Coelenterata
(c) Annelida
(d) Arthropoda
Answer:
(b) Coelenterata

 Samacheer Kalvi 9th Science Guide Chapter 17 Animal Kingdom

Question 3.
Which one of the following pairs is not a poikilothermic animal
(a) Fishes and Amphibians
(b) Amphibians and Aves
(c) Aves and Mammals
(d) Reptiles and Mammals
Answer:
(c) Aves and Mammals

Question 4
Identify the animal having four chambered heart.
(a) Lizard
(b) Snake
(c) Crocodile
(d) Calotes
Answer:
(c) Crocodile

 Samacheer Kalvi 9th Science Guide Chapter 17 Animal Kingdom

Question 5
The animal without skull is
(a) Acrania
(b) Acephalia
(c) Apteria
(d) Acoelomate
Answer:
(a) Acrania

Question 6.
Hermaphrodite organisms are
(a) Hydra, Tape worm, Earthworm, Amphioxus
(b) Hydra, Tape worm, Earthworm, Ascidian
(c) Hydra, Tape worm, Earthworm, Balanoglossus
(d) Hydra, Tape worm, Ascaris, Earthworm
Answer:
b) Hydra, Tap worm, Earthworm, Ascidian

Question 7.
Poikilothermic organisms are
(a) Fish, Frog, Lizard, Man
(b) Fish, Frog, Lizard, Cow
(c) Fish, Frog, Lizard, Snake
(d) Fish, Frog, Lizard, Crow
Answer:
(c) Fish, Frog, Lizard, Snake

 Samacheer Kalvi 9th Science Guide Chapter 17 Animal Kingdom

Question 8.
Air sacs and Pneumatic bones are seen in
(a) fish
(b) frog
(c) bird
(d) bat
Answer:
(c) Bird

Question 9.
Excretory organ of tape worm is
(a) flame cells
(b) nephridia
(c) body surface
(d) solenocytes
Answer:
(a) Flame cells

Question 10.
Water vascular system is found in
(a) Hydra
(b) Earth worm
(c) Star fish
(d) Ascaris
Answer:
(c) Starfish

 Samacheer Kalvi 9th Science Guide Chapter 17 Animal Kingdom

II. Fill in the blanks :

1. The skeletal framework of Porifera is ……………..
Answer:
spicules

2. Ctenidia are respiratory organs in ……………….
Answer:
phylum mollusca

3. Skates are ………………. fishes.
Answer:
cartilaginous

 Samacheer Kalvi 9th Science Guide Chapter 17 Animal Kingdom

4. The larvae of an amphibian is …………………..
Answer:
bilaterally symmetrical

5. ………………. are jawless vertebrates.
Answer:
Cyclostomes

6. …………………… is the unique characteristic feature of mammal.
Answer:
Placenta

 Samacheer Kalvi 9th Science Guide Chapter 17 Animal Kingdom

7. Spiny anteater is an example for …………….. mammal.
Answer:
egg-laying

III. State whether true or false. If false write the correct statement :

1. Canal system is seen in coelenterates.
Answer:
False.
Correct statement: Canal system is seen in porifera

2. Hermaphrodite animals have both male and female sex organs.
Answer:
True,

3. Trachea are the respiratory organ of Annelida.
Answer:
False.
Correct statement: Trachea are the respiratory organ of Arthopoda.

 Samacheer Kalvi 9th Science Guide Chapter 17 Animal Kingdom

4. Bipinnaria is the larva of Mollusca.
Answer:
False.
Correct statement: Bipinnaria is the larva of star fish.

5. Balanoglossus is a ciliary feeder.
Answer:
True.

6. Fishes have two chambered heart.
Answer:
True.

 Samacheer Kalvi 9th Science Guide Chapter 17 Animal Kingdom

7. Skin of reptilians are smooth and moist.
Answer:
False.
Correct statement: Skin of cyclostomata are smooth and moist.

8. Wings of birds are the modified forelimbs.
Answer:
True

9. Female mammals have mammary glands.
Answer:
True.

 Samacheer Kalvi 9th Science Guide Chapter 17 Animal Kingdom

IV. Match the following :

PHYLUM EXAMPLES
(A) Coelenterata (i) Snail
(B) Platyhelminthes (ii) Starfish
(C) Echinodermata (iii) Tapeworm
(D) Mollusca (iv) Hydra

Answer:
A – iv, B – iii, C – ii, D – i

V. Answer very briefly :

Question 1.
Define taxonomy.
Answer:
The theoretical study of classification includes its basic principles, procedures, and rules.

Question 2.
What is nematocyst?
Answer:
The tentacles of organisms belonging to phylum Coelenterata bear stinging cells called cnidoblast or nematocyst.

 Samacheer Kalvi 9th Science Guide Chapter 17 Animal Kingdom

Question 3.
Why coelenterates are called diploblastic animals?
Answer:
The animals in phylum coelenterates have two layers the outer ectoderm and the inner endoderm in the body wall. So they are called diploblastic animals.

Question 4.
List the respiratory organs of amphibians.
Answer:
Respiration is through by gills, skin, buccopharynx and lungs.

Question 5.
How does locomotion take place in starfish?
Answer:
Locomotion is affected by tube feet.

 Samacheer Kalvi 9th Science Guide Chapter 17 Animal Kingdom

Question 6.
Are jellyfish and starfish similar to fishes? If no justify the answer.
Answer:

  • Jellyfish is a coelenterate. Their bodies are made of calcium carbonate.
  • Starfish fish is an echinoderm. Their bodies are made of calcium carbonate.
  • Catfish is a fish species.
  • Jellyfish and starfish are invertebrates.
  • Fishes are vertebrates.

Question 7.
Why are frogs said to be amphibians?
Answer:
The frogs have dual adaptation in land and aquatic environments. So they are called amphibians.

VI. Answer briefly:

Question 1.
Give an account on phylum Annelida.
Answer:

  • These are bilaterally symmetrical, triploblastic, first true coelomate animals with an organ-system grade of organization.
  • Body is externally divided into segments called metameres joined by ring-like structures called annuli.
  • It is covered by a moist thin cuticle.
  • Setae and parapodia are locomotor organs.
  • Sexes may be separate or ünited (hermaphrodites).
    e.g- Nereis, Earthworm, Leech.

 Samacheer Kalvi 9th Science Guide Chapter 17 Animal Kingdom

Question 2.
Differentiate between flatworms and roundworms?
Answer:

Flatworms Roundworms
a) They belong to Phylum Platyhelminthes. They belong to Phylum Aschelminthes.
b) They are mostly parasitic. Exist as free-living soil forms or as parasites.
c) Mostly hermaphrodites. Sexual dimorphism is seen.
d) They are acoelomate organisms. They are pseudocoelomate organisms.
e) The alimentary canal is absent or simple.
Eg: Tapeworm.
The alimentary canal is a straight tube.
Eg: Roundworm.

Question3.
Outline the flow charts of Phylum Chordata.
Answer:
Classification of phylum Chordata:
Samacheer Kalvi 9th Science Guide Chapter 17 Animal Kingdom 1

Question 4.
List five characteristic features of fishes.
Answer:

  • Fishes are poikilothermic, whose internal temperature varies, considerably.
  • The body has a covering of scales.
  • Body muscles are arranged into segments called myotomes.
  • The body is differentiated into head, trunk and tail.
  • Respiration is done by 5 to7 pairs of gills, which are covered by an operculum or sometimes maybe naked.

 Samacheer Kalvi 9th Science Guide Chapter 17 Animal Kingdom

Question 5.
Comment on the aquatic and terrestrial habits of amphibians.
Answer:
Aquatic habits of amphibians:

  • The larva of amphibians (tadpole) lives in water and breathes with gills.
  • External fertilization occurs in frog with water as a medium of fertilization.
  • The adult frog has webbed feet to swim in water.
  • The skin is moist and glandular which helps in Respiration.

Terrestrial habits of amphibians:

  • The adults live on land and breathe through the lungs. Bucco-pharynx also helps in Respiration.
  • The forelimbs are short and help to hop on land.

Question 6.
How are the limbs of the birds adapted for avian life?
Answer:

  1. Birds have a spindle-shaped body.
  2. The forelimbs are modified as wings for aerial locomotion.
  3. The air sacs present in the birds, make the bird lightweight.
  4. The body is covered with feathers.

 Samacheer Kalvi 9th Science Guide Chapter 17 Animal Kingdom

VII. Answer in detail :

Question 1.
Describe the characteristic features of different Prochordates.
Answer:
Prochordata :

  • The urochordates are considered as the forerunner of vertebrates.
  • Based on the nature of the notochord, protochordate is classified into subphylum Urochordata and subphylum Cephalochordata.
    Phylum Hemichordata :
    Samacheer Kalvi 9th Science Guide Chapter 17 Animal Kingdom 2
  • Hemichordates are marine organisms with soft, vermiform and unsegmented body.
  • They are bilaterally symmetrical, coelomate animals with non-chordate and chordate features.
  • They have gill slits but do not have notochord.
  • They are ciliary feeders and mostly remain as tubiculous forms, e.g- Balanoglossus (Acorn worms).
    Subphylum Urochordata:
    Samacheer Kalvi 9th Science Guide Chapter 17 Animal Kingdom 3
  • Notochord is present only in the tail region of free-living larva, e.g. Ascidian
  • Adults are sessile forms and mostly degenerate.
  • The body is covered with a tunic or test.

Subphylum Cephalochordata :

  • Cephalochordates are small fish like marine chordates with unpaired dorsal fins.
  • The notochord extends throughout the entire length of the body. e.g. Amphioxus

Question 2.
Give an account on phylum Arthropoda.
Answer:

  • Arthropoda is the largest phylum.
  • The organisms have jointed legs.
  • The body is segmented into head, thorax and abdomen.
  • The exoskeleton is made up of chitin.
  • The coelomic cavity is filled with haemolymph (blood).
  • They do not have defined blood vessels. This is called open circulatory system.
  • The insects shed the exoskeleton and this process is called moulting.
  • Small Arthropods absorb oxygen through the body and larger aquatic species breathe through book gills.
  • Land Arthropods breathe through a system of tiny body tubes called tracheae.
  • Excretion occurs through malphigian tubules and through green glands in crabs and prawns. .
  • Insects, spiders, crabs, shrimps, butterflies, millipedes, centipedes, and scorpions are some arthropods.

 Samacheer Kalvi 9th Science Guide Chapter 17 Animal Kingdom

Intext activities

ACTIVITY – 1
Samacheer Kalvi 9th Science Guide Chapter 17 Animal Kingdom 5
Observation :

  • Scorpion
  • Arachnid
  • Cockroach
  • Crab
  • Crustacean
    [End of the activity]

9th Science Guide Animal Kingdom Additional Important Questions and Answers

I. Choose the correct answer:

Question 1.
Which is not an insect?
(a) Housefly
(b) Bedbug
(c) Mosquito
(d) Spider
Answer:
d) Spider

Question 2.
Which is not a feature of chordates?
(a) Green glands
(b) Sweat glands
(c) Sebaceous gland
(d) Mammary gland
Answer:
(a) Green glands

 Samacheer Kalvi 9th Science Guide Chapter 17 Animal Kingdom

Question 3.
Choose the correct terms related to Hemichordate
(a) Vermiform, unsegmented, bilaterally symmetrical, ciliary feeders
(b) Vermiform, segmented, triploblastic, ciliary feeders
(c) Vermiform, unsegmented, diploblastic, ciliary feeders
(d) Vermiform, unsegmented; triploblastic, filter feeders
Answer:
a) Vermiform, unsegmented, bilaterally symmetrical, ciliary feeders

Question 4.
The …………. can swim faster than a cheetah.
(a) Sail fish
(b) Catfish
(c) Jelly fish
(d) Sucker fish
Answer:
a) Sail fish

 Samacheer Kalvi 9th Science Guide Chapter 17 Animal Kingdom

Question 5.
The biggest vertebrate animal is the ……………….
(a) Blue whale
(b) Dolphin
(c) Elephant
(d) Rhinoceros
Answer:
(a) Blue whale

Question 6.
Who introduced binomial nomenclature?
(a) Huxley
(b) Carolus Linnaeus
(c) Nicolaus Copernicus
(d) Charles Darwin
Answer:
(b) Carolus Linnaeus

 Samacheer Kalvi 9th Science Guide Chapter 17 Animal Kingdom

Question 7.
What is the binomial name of tapeworm?
(a) Ascaris lumbricoides
(b) Taenia solium
(c) Lampito mauritii
(d) Hirudinaria granulosa
Answer:
(b) Taenia solium

Question 8.
Which is the state bird of Tamil Nadu?
(a) Peacock
(b) Parrot
(c) Emerald dove
(d) Eagle
Answer:
(c) Emerald dove

Question 9. ;
……………. is an example of bony fish.
(a) Mullets
(b) Sharks
(c) Skates
(d) Hagfish
Answer:
(a) Mullets

 Samacheer Kalvi 9th Science Guide Chapter 17 Animal Kingdom

Question 10.
The notochord extends throughout the entire length of the body.
(a) Acorn worms
(b) Lamprey
(c) Ascidian
(d) Amphioxus
Answer:
(d) Amphioxus

Question 11.
Animals which possess notochord are called as …………………
(a) invertebrates
(b) non-chordates
(c) chordates
(d) all the above
Answer:
(c) chordates

 Samacheer Kalvi 9th Science Guide Chapter 17 Animal Kingdom

Question 12.
What ¡s the name of the bone which is filled with air?
(a) Flat bones
(b) Irregular bones
(c) Short bones
(d) Pneumatic bones
Answer:
d) Pneumatic bones

Question 13.
_________ ¡s the unique characteristic feature of mammals.
(a) Placenta
(b) Egg
(c) Tail
(d) Ear
Answer:
(a) Placenta

Question 14.
________ have gill slits but do not have notochord.
(a) Phylum Hemichordata
(b) Phylum Echirodermata
(c) Phylum Mollusca
(d) Phylum Annelida
Answer:
Phylum Hemichordata

 Samacheer Kalvi 9th Science Guide Chapter 17 Animal Kingdom

II. Fill In the blanks:

1. The binomial name of our National Bird is …………………………
Answer:
pavocristatus

2. In mammals testis are enclosed by ………………….
Answer:
scrotal sacs

3. In birds, the air sacs communicate with …………………
Answer:
lungs

 Samacheer Kalvi 9th Science Guide Chapter 17 Animal Kingdom

4. The animals belonging to phylunm …………….. are said to be soft-bodied.
Answer:
mollusca

5. The name ………….. means “thousand legs”.
Answer:
millipede

6. The skeletal framework of phylum Porifera is made up of ……………..
Answer:
spicules

 Samacheer Kalvi 9th Science Guide Chapter 17 Animal Kingdom

7. A true body cavity is located within ………………
Answer:
mesoderm

8………………. separates the digestive tract from the body wall.
Answer:
Coelom

9. ……………….. formed during embryonic development.
Answer:
Notochord

 Samacheer Kalvi 9th Science Guide Chapter 17 Animal Kingdom

10. …………….. is the largest phylum of the animal kingdom.
Answer:
Arthropoda

11. ………………… is a fluid-filled body cavity.
Answer:
Coelom

12. The body cavity of the phylum Aschelminthes is …………………….
Answer:
pseudocoelom

 Samacheer Kalvi 9th Science Guide Chapter 17 Animal Kingdom

13. The most common diseases caused by nematodes in human beings are …………and ……………
Answer:
elephantiasis, ascariasis

14. Cyclostmes are ………………….
Answer:
jawless vertebrates

15. Malphigian tubules also called as ……………….
Answer:
green glands

 Samacheer Kalvi 9th Science Guide Chapter 17 Animal Kingdom

16. Locomotion of phylum Echinodermata is affected by .
Answer:
tube feet

III. Analogy:

Question 1.
Echinodermata: ________ : : Soft Bodies Animals: ________
Answer:
Spiny Skinned Animals; Mollusca.

Question2.
Birds: _______ : : _________ : Cold-blooded.
Answer:
Warm-blooded; Fishes.

IV. State whether true or false. If false write the correct statement:

1. Order is a number of related families having common characters are placed in an order.
Answer:
True.

2. Tissue organization can be seen in phylum Porifera.
Answer:
False.
Correct statement: Cellular grade of organization can be seen in phylum Porifera.

 Samacheer Kalvi 9th Science Guide Chapter 17 Animal Kingdom

3. Aschelminthes is the largest phylum of the animal kingdom.
Answer:
False.
Correct statement: Arthropods is the largest phylum of the animal kingdom.

4. In the animals belonging to phylum Echinodermata, the body is divided into head, muscular food and visceral mass………….
Answer:
False.
Correct statement: In phylum mollusca, the body is divided into head, muscular food and visceral mass.

5. Setae and parapodia are locomotor organs of earthworms.
Answer:
True.

 Samacheer Kalvi 9th Science Guide Chapter 17 Animal Kingdom

6. Mammals have four-chambered Hearts.
Answer:
True,

V. Match the following:

Question 1.

(A) Cartilaginous (i) Mullets
(B) Bony fishes (ii) Sharks
(C) Pneumatic bones (iii) Reptiles
(D) Three chambered heart (iv) Birds

Answer:
A – i, B – ii, C – iv, D – iii

 Samacheer Kalvi 9th Science Guide Chapter 17 Animal Kingdom

VI. Assertion and Reason type :

Question 1.
Assertion (A) : The Arthropods have an open circulatory system. .
Reason (R) : The cells and tissues are bathed in blood.
(a) A is right and R is wrong.
(b) A is the wrong R is right.
(c) A and R are wrong.
(d) A is right R explains A.
Answer:
(d) A is right R explains A

Question 2.
Assertion (A) : Mammals give birth to their young ones.
Reason (R) : Platypus is an egg-laying mammal.
(a) A and R are correct.
(b) A and R are wrong.
(c) R explains A.
(d) A is the wrong R is right.
Answer:
(a) A and R are correct

 Samacheer Kalvi 9th Science Guide Chapter 17 Animal Kingdom

VII. Answer in one or two sentences :

Question 1.
Which organism is called Friends of farmers? Why?
Answer:
Earthworms are called ‘Friends of the farmers’ because after digesting organic matter, earthworms excrete a nutrient-rich waste product called castings which are used as Vermicompost.

Question 2.
What are the sub-phylum of prochordates?
Answer:
Sub phylum of prochordates are
Subphylum Cephalochordata
Subphylum Urochordata

Question 3.
Name the three germ layers.,
Answer:
Ectoderm, mesoderm and endoderm

 Samacheer Kalvi 9th Science Guide Chapter 17 Animal Kingdom

Question 4.
Name the locomotary organs seen in phylum protozoa.
Answer:
Pseudopodia, cilia, or flagella.

Question 5.
Mention two special features of mammals.
Answer:
(i) External ear or pinna is seen in most the mammals.
(ii) Presence of the placenta is a unique characteristic feature.

Question 6.
Write the binomials of a) Man b) Tapeworm
Answer:
a) Homo sapiens
b) Taenia solium.

 Samacheer Kalvi 9th Science Guide Chapter 17 Animal Kingdom

Question 7.
What is the binomial name?
Answer:
Carolus Linnaeus introduced the method of naming the animals with two names. This is known as binomial name and is followed universally.
Eg: Binomial of frog is
Samacheer Kalvi 9th Science Guide Chapter 17 Animal Kingdom 6

VIII. Short answer questions :

Question 1.
How is the body wall of coelenterates arranged?
Answer:
Body wall of coelenterate is disloblastic with two layers, namely the outer ectoderm and the inner endoderm, are separated by non-cellular jelly-like substance called mesoglea. Due to the presence of two layers in the body wall, they are said to be diploblastic animals.

Question 2.
What is polymorphism?
Answer:
Many coelenterates exhibit polymorphism, which is the variation in the structure and function of the individuals of the same species. They reproduce both asexually and sexually, e.g. Hydra, Jellyfish.

 Samacheer Kalvi 9th Science Guide Chapter 17 Animal Kingdom

Question 3.
What is the unique feature of chordates?
Answer:
Presence of notochord is the unique feature of chordates.

Question 4.
On the basis of position of notochord, classify the different prochordates. Justify your answer.
Answer:

Subphyla of prochordates Position of notochord
b) Cephalochordata The notochord is present only in the tail region of the free-living larva. e.g. Ascidian
c) Urochordata The notochord extends throughout the entire length of the body. e.g. Amphioxus

Question 5.
List the integumentary glands of mammals.
Answer:
Integumentary glands are seen in mammals:

  • Sweat glands
  • Sebaceous glands
  • Scent glands
  • Mammary glands are modified
  • Integumentary glands

 Samacheer Kalvi 9th Science Guide Chapter 17 Animal Kingdom

Question 6.
How is the reproductive characters of mammals different from those of aves.

Mammals

Aves

(i) Mammals have paired sex organs, eggs are small with little or no yolk. (i) They are oviparous and lay eggs.
(ii) They are viviparous and give birth to young one. (ii) Formation of placenta is not seen. The embryo is nourished,by egg yolk. Egg has an abundant quantity of yolk.
(iii) Formation of placenta is a special feature. The tissue connects the foetus to maternal tissues.

Question 7.
Mention two characteristic features of phylum Echinodermata.
Answer:
They have a water vascular system which is a unique feature. Locomotion is affected by tube feet.

Question 8.
Mention two features seen in Aves to aid in flying.
Answer:

  • The forelimbs are modified into wings for flight.
  • Bones are filled with air (pneumatic bones), which reduces body weight.

 Samacheer Kalvi 9th Science Guide Chapter 17 Animal Kingdom

Question 9.
Why is crocodile unique among reptiles?
Answer:
It has a four-chambered heart whereas the reptiles have a three-chambered heart.

Question 10
Why are eggs of reptiles covered with shell unlike eggs of amphibians?
Answer:
First-class of vertebrates adapted for terrestrial life and lay their eggs with tough outer Shell e.g Calotes, Lizard, Snake, Tortoise, Turtle. Hence the eggs are covered with shells to protect them. Whereas amphibians eggs are laid in water.

Question 11.
What are pneumatic bones?
Answer:
The bones are filled with air. So they are called pneumatic bones and are seen in aves.

 Samacheer Kalvi 9th Science Guide Chapter 17 Animal Kingdom

IX. Long answer questions :

Question 1.
Write a note on mammals.
Answer:

  • Mammals are -warm-blooded animals.
  • The skin is covered with hair. It also bears sweat and sebaceous (oil) glands.
  • The body is divisible into head, neck, trunk and tail.
  • Females have mammary glands, which secrete milk for feeding the young ones.
  • The external ear or pinnae is present.
  • Heart is four-chambered and they breathe through lungs.
  • Except egg-laying mammals (Platypus, and Spiny anteater), all other mammals give birth to their young ones (viviparous).
  • Placenta is the unique characteristic feature of mammals, e.g Rat, Rabbit, Man.

Question 2.
Write a note on aves.
Answer:

  • Birds are homeothermic (warm-blooded) animals with several adaptations to fly.
  • The spindle or boat-shaped body is divisible into head, neck, trunk and tail.
  • The body is covered with feathers. Forelimbs are modified into wings for flight.
  • Hindlimbs are adapted for walking, perching or swimming.
  • The respiration is through lungs, which have air sacs.
  • Bones are filled with air (pneumatic bones), which reduces body weight.
  • They lay large yolk laden eggs.
  • They are covered by hard calcareous shell, e.g. Parrot, Crow, Eagle, Pigeon, Ostrich.

Question 3.
Outline the flow chart of invertebrate phyla.
Answer:
Samacheer Kalvi 9th Science Guide Chapter 17 Animal Kingdom 7

Samacheer Kalvi 9th Science Guide Chapter 19 Plant Physiology

Tamilnadu State Board New Syllabus Samacheer Kalvi 9th Science Guide Pdf Chapter 19 Plant Physiology Text Book Back Questions and Answers, Notes.

Tamilnadu Samacheer Kalvi 9th Science Solutions Chapter 19 Plant Physiology

9th Science Guide Plant Physiology Text Book Back Questions and Answers

Samacheer Kalvi 9th Science Guide Chapter 20 Organ Systems in Animals

I. Choose the correct answer :

Question 1.
The tropic movement that helps the climbing vines to find a suitable support is …………….
(a) phototropism
(c) thigmotropism
(b) geotropism
(d) chemotropism
Answer:
(c) thigmotropism

Question 2.
The chemical reaction occurs during photosynthesis is .
(a) CO2 is reduced and water is oxidized
(b) water is reduced and CO2 is oxidized
(c) both CO2 and water are oxidized
(d) both CO2 and water are produced
Answer:
(a) CO2 is reduced and water is oxidized

Question 3.
The bending of root of a plant in response to water is called …………………….
(a) Thigmonasty
(b) Phototropism
(c) Hydrotropism
(d) Photonasty
Answer:
(c) Hydrotropism

Samacheer Kalvi 9th Science Guide Chapter 20 Organ Systems in Animals

Question 4.
A growing seedling is kept in the dark room. A burning candle is placed near it for a few days. The tip part of the seedling bends towards the burning candle. This is an example of ……………
(a) Chemotropism
(b) Geotropism
(c) Phototropism
(d) Thigmotropism
Answer:
(c) Phototropism

Question 5.
The root of the plant is …………………
i) positively phototropic but-negatively geotropic
ii) positively geotropic but negatively phototropic
iii) negatively phototropic but positively hydrotropic
iv) negatively hydrotropic but.positively phototropic
(a) (i) and (ii)
(b) (ii) and (iii)
(c) (iii) and (iv)
(d) (i) and (iv)
Answer:
(b) (ii) and (iii)

Samacheer Kalvi 9th Science Guide Chapter 20 Organ Systems in Animals

Question 6.
The non-directional movement of a plant part in response to temperature is called………………..
(a) Thermotropism
(b) Thermonasty
(c) Chemotropism
(d) Thigmonasty
Answer:
(b) Thermonasty

Question 7.
Chlorophyllin a leaf is required for …………………
(a) photosynthesis
(b) tropic movement
(c) transpiration
(d) nastic movement
Answer:
(a) photosynthesis

Samacheer Kalvi 9th Science Guide Chapter 20 Organ Systems in Animals

Question 8.
Transpiration takes place through ………………..
(a) fruit
(b) seed
(c) flower
(d) stomata
Answer:
(d) stomata

II. Fill in the blanks :

1. The shoot system grows upward in response to ………………..
Answer:
light

2. ………………..is positively hydrotropic as well as positively geotropic.
Answer:
root

3. The green pigment present in the plant is………………..
Answer:
chlorophyll

Samacheer Kalvi 9th Science Guide Chapter 20 Organ Systems in Animals

4. The solar tracking of sunflower in accordance with the path of sun is due to …………………
Answer:
phototropism:

5. The response of a plant part towards gravity is ………………..
Answer:
geotropism

6. Plants take in carbon dioxide for photosynthesis but need ……………….. for their living.
Answer:
oxygen

III. Match column A with column B

Column A

Column B

1. Roots growing downwards into soil. Positive phototropism
2. Shoots growing towards the light. Negative geotropism
3. Shoots growing upward. Negative phototropism
4. Roots growing downwards away from light. Positive geotropism

Answer:

Column A Column B
1. Roots growing downwards into soil. Positive geotropism
2. Shoots growing towards the light. Positive phototropism
3. Shoots growing upward. Negative geotropism
4. Roots growing downwards away from light. Negative phototropism

IV. State whether true or false. If false, correct the statement:

1. The response of a part of plant to the chemical stimulus is called phototropism.
Answer:
False.
Correct statement : The response of a plant part to the chemical stimulus is called Itemoiropisin.

2. Shoot is positively phototropic and negatively geotropic.
Answer:
True.

Samacheer Kalvi 9th Science Guide Chapter 20 Organ Systems in Animals

3. When the weather is hot, water evaporates lesser which is due to opening of stomata.
Answer:
False.
Correct statement: When the weather is hot, water evaporates more but stomata begin to close to reduce evaporation.

4. Photosynthesis produces glucose and carbon dioxide.
Answer:
False.
Correct statement: Photosynthesis produces glucose and oxygen.

5. Photosynthesis is important in releasing oxygen to keep the atmosphere in balance.
Answer:
True

Samacheer Kalvi 9th Science Guide Chapter 20 Organ Systems in Animals

6. Plants lose water when the stomata on leaves are closed.
Answer:
False.
Correct statement: Plants lose water when the stomata on leaves are open.

V. Answer very briefly :

Question 1.
What is nastic movement?
Answer:
Non-directional response to the stimulus is called Nastic movements.

Question 2.
Name the plant part
a) Which bends in the direction of gravity but away from the light.
b) Which bends towards the light but away from the force of gravity.
Answer:
a) Root system
b) Shoot system.

Samacheer Kalvi 9th Science Guide Chapter 20 Organ Systems in Animals

Question 3.
Differentiate phototropism from photo nasty.
Answer:
Phototropism:

  1. Movement of a plant part towards the light.
  2. Eg: Shoot of a plant.

Photonasty:

  1. Movement of a plant part is a response to light.
  2. Eg: Moonflower, Taraxacum Officinale.

Question 4.
Photosynthesis converts energy X into energy Y.
a) What are X and Y?
b) Green plants are autotrophic in their mode of nutrition. Why?
Answer:
a) X → light energy,
Y → Chemical energy.
b) Green plants are autotrophic in their mode of nutrition because they prepare then- own food materials through photosynthesis.

Question 5.
Define transpiration.
Answer:
The loss of water in the form of water vapour from the aerial parts of the plant body is called Transpiration.

Samacheer Kalvi 9th Science Guide Chapter 20 Organ Systems in Animals

Question 6.
Name the cell that surrounds the stoma.
Answer:
Each stomata is surrounded by guard cells.

VI. Answer briefly :

Question 1.
Give the technical terms for the following :
a) Growth dependent movement in plants.
b) Growth independent movement in plants.
Answer:
a) Tropic movements
b) Nastic movements

Question 2.
Explain the movement seen in Pneumatophores of Avicennia.
Answer:

  • Pneumato[hores are specialized roots that can involve in the respiration of plants,
  • This type of roots intakes the gas through its lenticel. a small hole in their both.

Question 3.
Fill in the blanks:
Samacheer Kalvi 9th Science Guide Chapter 19 Plant Physiology 1
Answer:
Samacheer Kalvi 9th Science Guide Chapter 19 Plant Physiology 2

Samacheer Kalvi 9th Science Guide Chapter 20 Organ Systems in Animals

Question 4.
What is chlorophyll?
Answer:
Chlorophyll is a green pigment present in all green plants with is responsible for the absorption of light to provide energy for photosynthesis.

Question 5.
Name the part of plant which shows positive geotropism. Why?
Answer:
Root shows positive geotropism because of the unidirectional movement in response to gravity.

Question 6.
What is the difference between the movement of flowers in the sunflower plant and the closing of the leaves in the Mimosa pudica?
Answer:
Movement of flower in sunflower plant:
In sunflower plant the stem tip follows the path of the sun from dawn to dusk (East to est) and in night it moves from West to East. This is a growth movement and takes place in response to the stimulus ‘light’. It is an example of tropic movement in response to light and is called phototropism.

Closing of the leaves in the Mimosa pudica :
The closing of leaves in Mimosa pudica occurs in response to touch. It is not a growth movement and occurs independently of the direction of stimulus. This is nastic movement . and is called Thigmonasty.

Samacheer Kalvi 9th Science Guide Chapter 20 Organ Systems in Animals

Question 7.
Suppose you have a rose plant growing in a pot, how will you demonstrate transpiration in it?
Answer:
Tie a plastic bag over leaves of rose plant and place in sunlight. After a few hours, we see water condensing inside the plastic bag. This is due to loss of water in the form of water vapour, which condenses into water. This is due to transpiration.

Question 8.
Mention the differences between stomatal and lenticular transpiration.
Answer:
Stomatal transpiration :

  1. Loss of water from plants through stomata.
  2. 90-95% of transpiration in a plant takes place through stomata only.

Lenticular transpiration :

  1. Loss of water from plants as vapour through the lenticels.
  2. A very small percentage of water is lost by through plants lenticular transpiration.

Question 9.
To which directional stimuli do (a) roots respond (b) shoots respond?
Answer:
(a) Roots respond positively geostrophic and negatively phototrophic.
(b) Shoots respond negatively geostrophic and positively phototrophic.

Samacheer Kalvi 9th Science Guide Chapter 20 Organ Systems in Animals

VII. Answer in detail :

Question 1.
Differentiate between tropic and nastic movements
Answer:
Tropic movements

  1. Unidirectional response to the stimulus.
  2. Growth dependent movements.
  3. More or less permanent and irreversible.
  4. Found in all plants.
  5. Slow action.

Nastic movements :

  1. Non-directional response to the stimulus
  2. Growth independent movements. –
  3. Temporary and reversible.
  4. Found only in a few specialized plants.
  5. Immediate action.

Question 2.
How will you differentiate the different types of transpiration?
Answer:
There are three types of transpiration:
Stomatal transpiration: Loss of water from plants through stomata. It accounts for 90- 95% of the water transpired from leaves.
Cuticular transpiration: Loss of water in plants through the cuticle.
Lenticular transpiration: Loss of water from plants as vapour through the lenticels. The lenticels are tiny openings that protrude from the barks in woody stems and twigs as well as in other plant organs.
But transpiration is necessary for the following reasons.

  1. It creates a pull in leaf and stem.
  2. It creates an absorption force in roots.
  3. It is necessary for a continuous supply of minerals.
  4. It regulates the temperature of the plant.

VIII. Higher Order Thinking Skills:

Question 1.
There are 3 plants A, B and C. The flowers of A open their petals in bright light during the day but closes when it gets dark at night. On the other hand, the flowers f of plant B open their petals at night but closes during the day when there is a bright light. The leaves of plant C fold up and droop when touched with fingers or any other solid object.
(a) Name the phenomenon shown by the flowers of plants A and B.
(b) Name one plant each which behaves like the flowers of plant A and B.
(c) Name the phenomenon exhibited by the leaves of plant C.
Answer:
(a) Photonasty
(b) Plant A – Common Dandelion – Taraxacum officinale
Plant B – Moonflower – Ipomoea alba
(c) Nyctinasty

Samacheer Kalvi 9th Science Guide Chapter 20 Organ Systems in Animals

Question 2.
Imagine that student A studied the importance of certain factors in photosynthesis.
He took a potted plant and kept it in dark for 24 hours. In the early hours of the next
morning, he covered one of the leaves with dark paper in the centre only. Then he placed the plant in sunlight for a few hours and tested the leaf which was covered
with black paper for starch.
(a) What aspect of photosynthesis was being investigated?
(b) Why was the plant kept in the dark before the experiment?
(c) How will you prove that starch is present in the leaves?
Answer:
(a) Necessity of light as a factor for Photosynthesis.
(b) To make the plant starch-free before starting the experiment. After the experiment, if starch is found in the leaf it will be the starch prepared by leaves during the experiment only.
(c) Presence of starch in the leaves can be proved by doing the starch test.

  • The potted plant is kept in bright sunlight for 4 to 6 hours.
  • The selected covered leaf is plucked and the black paper is removed.
  • The leaf is immersed in boiling water for a few minutes and then in alcohol to remove chlorophyll.
  • The leaf is now tested with iodine solution for the presence of starch.
  • The covered part of the leaf does not turn blue-black whereas the uncovered part of the leaf turns blue-black colour.
  • The covered part of the leaf which did not receive the sunlight was unable to synthesize starch.
  • Hence it does not turn blue-black colour.
  • But the uncovered part of the leaf which received sunlight was able to synthesize starch and so it turns blue-black in colour.

Intext Activities

ACTIVITY – 1

Take a glass trough and fill it with sand. Keep a flower pot containing water, plugged at the bottom at the centre of the glass trough. Place some soaked pea or bean seeds around the pot in the sand. What do you observe after 6 or 7 days? Record your observation.

Aim : To demonstrate hydrotropism.
Materials required : Glass trough, sand, flower pot, plugged at the bottom, pea or bean seeds and water.

Samacheer Kalvi 9th Science Guide Chapter 19 Plant Physiology 3

Samacheer Kalvi 9th Science Guide Chapter 20 Organ Systems in Animals

Procedure :

  1. A glass trough is taken and is filled with sand. A flowerpot containing water plugged at the bottom is kept at the centre of the glass trough.
  2. Soaked pea or bean seeds are placed around the pot in the sand. It is observed after 6 or 7 days.

Observation: Observed that radicle has grown towards the pot and moisture instead of growing vertically downward.
Inference: It proves that primary root is positively hydrotropic.
Result: Hydrotropism has been demonstrated by showing positive hydrotropism in roots.

[End of the activity]

ACTIVITY – 2

Take pea seeds soaked in water overnight. Wait for the pea seeds to germinate. Once the seedling has grown put it in a box with an opening for light on one side. After few hours, you can clearly see how the stem has bent and grown towards the light.

Aim : To demonstrate phototropism.
Materials required : Box, water, light and pea seeds.

Procedure:

  1. Take pea seeds soaked in water overnight. Wait for the pea seeds to germinate.
  2. Once the seedling has grown put it in a box with an opening for light on one side.
  3. After few hours, you can clearly see how the stem has bent and grown towards the light.

Observation : Observed that movement of a stem of a plant (pea seeds) towards light moist condition. This is the way a new plant develops from a seed.
Inference : Positive phototropism of a plant has been demonstrated.

[End of the activity]

ACTIVITY – 3

Pluck a variegated leaf from Coleus plant kept in sunlight. De- starch it by keeping in dark room for 24 hours. Draw the picture of this leaf and mark the patches of cholorphyll on the leaf. Immerse the leaf in boiling water followed by alcohol and test it for starch using iodine solution. Record your observation.

Aim : To show that chlorophyll is essential for photosynthesis.
Materials required : Plant with variegated leaves, boiling water, alcohol and iodine solution.
Samacheer Kalvi 9th Science Guide Chapter 19 Plant Physiology 4

Procedure:
Variegated leaf is plucked from Coleus plant kept in sunlight. It isde-starched by keeping it in dark room for 24 hours. The picture of this leaf is drawn and the patches of cholorphyll on the leaf are marked. After immersing the leaf in boiling water followed by alcohol it is tested for starch with iodine solution.

Observation : The patches of the leaf with chlorophyll turn blue-black. The other portions remain colourless.
Inference: The chlorophyll is essential for photosynthesis.

Samacheer Kalvi 9th Science Guide Chapter 20 Organ Systems in Animals

ACTIVITY – 4

Place a potted plant in a dark room for about 2 days to de-starch its leaves. Cover one of its leaves with the thin strip of black paper as shown in the picture, make sure that the leaf is covered on both sides. Keep the potted plant in bright sunlight for 4 to 6 hours. Pluck the selected covered leaf and remove the black paper.
Immerse the leaf in boiling water for a few minutes and then in alcohol to remove chlorophyll. Test the leaf now with iodine solution for the presence of starch. The covered part of the leaf does not turn blue-black whereas the uncovered part of the leaf turns blue-black colour. Why are the changes in colour noted in the covered and uncovered part of the leaf?
Samacheer Kalvi 9th Science Guide Chapter 19 Plant Physiology 5

Aim : To show that light is essential for photosynthesis.
Materials required : Covered leaf, boiling water, alcohol and iodine.

Procedure:

  1. A potted plant is placed in a dark room for about 2 days to de-starch its leaves.
  2. One of its leaves is covered with a thin strip of black paper as shown in the picture.
  3. Make sure that the leaf is covered on both sides.
  4. The potted plant is kept in bright sunlight for 4 to 6 hours.
  5. The selected covered leaf is plucked and the black paper is removed.
  6. Th e leaf is immersed in boiling water for a few minutes and then in alcohol to remove chlorophyll.
  7. The leaf is now tested with iodine solution for the presence of starch.

Observation : The covered part of the leaf does not turn blue-black whereas the uncovered part of the leaf turns blue black colour. The covered part of the leaf which did not receive sunlight was unable to synthesize starch.
Inference : The light is essential for photosynthesis.

9th Science Guide Plant Physiology in Animals Additional Important Questions and Answers

I. Choose the correct answer :

Question 1.
The bending of root of a plant in response to water is called …………………..
(a) thigmonasty
(b) phototropism
(c) hydrotropism
(d) photonasty
Answer:
(c) hydrotropism

Question 2.
A growing seedling is kept in the dark room. A burning candle is placed near it for a few days. The top part of the seedling bends towards the burning candle. This is an example of ……………………
(a) chemotropism
(b) thigmotropism
(c) phototropism
(d) geotropism
Answer:
(c) phototropism

Question 3.
The root of the plant is ……………………
(i) positively phototropic but negatively geotropic.
(ii) positively geotropic but negatively phototropic.
(iii) negatively phototropic but positively hydrotropic.
(iv) negatively hydrotropic but positively phototropic.
(a) (i) and (ii)
(b) (ii) and (iii)
(c) (iii) and (iv)
(d) (i) and (iv)
Answer:
(b) (ii) and (iii)

Samacheer Kalvi 9th Science Guide Chapter 20 Organ Systems in Animals

Question 4.
The plant part which exhibits negative geotropism is ……………………
(a) root
(b) stem
(c) branch
(d) leaves
Answer:
(b) stem

Question 5.
The non-directional movement of a plant part in response to temperature is called…………………..
(a) thermotropism
(b) thermonasty
(c) chemotropism
(d) thigmonasty
Answer:
(b) thermonasty

Samacheer Kalvi 9th Science Guide Chapter 20 Organ Systems in Animals

Question 6.
Sunflowers open the petals in bright light during the day time but close the petals in dark at night. This response of sunflowers is called ……………………
(a) geonasty
(b) thigmonasty
(c) chemonasty
(d) photonasty
Answer:
(d) photonasty

Question 7.
During photosynthesis plants exhale ……………………
(a) Carbon dioxide
(b) oxygen
(c) hydrogen
(d) helium
Answer:
(b) oxygen

Samacheer Kalvi 9th Science Guide Chapter 20 Organ Systems in Animals

Question 8.
Chlorophyll in a leaf is required for ……………………
(a) photosynthesis
(b) transpiration
(c) tropic movement
(d) nastic movement
Answer:
(a) photosynthesis

Question 9.
A plant is kept in a dark room for about 24 hours before conducting any experiment on photosynthesis in order to ……………………
(a) remove chlorophyll from the leaf
(b) remove starch from the leaves
(c) ensure that photosynthesis occurred
(d) to prove transpiration
Answer:
(b) remove starch from the leaves

Question 10.
Transpiration takes place through ……………………
(a) fruit
(b) seed
(c) flower
(d) stomata
Answer:
(d) stomata

Samacheer Kalvi 9th Science Guide Chapter 20 Organ Systems in Animals

Question 11.
Thigmonasty can be seen in ……………………
(a) Mimosa pudica
(b) Taraxacum officinale
(c) Ipomea alba
(d) Rhizophora
Answer:
(a) Mimosa pudica

Question 12.
The venus flytrap plants are examples for …………………..
(a) chemotropism
(b) thigmonasty
(c) hydrotropism
(d) thigmotropism
Answer:
(b) thigmonasty

Question 13.
………………….. flowers bloom as the temperature increases.
(a) Rose
(b) Jasmine
(c) Lilly
(d) Tulip
Answer:
(d) Tulip

Samacheer Kalvi 9th Science Guide Chapter 20 Organ Systems in Animals

Question 14.
Only green plants have the unique capacity to release ………………….. into the atmosphere.
(a) nitrogen
(b) oxygen
(c) carbon dioxide
(d) ozone
Answer:
(b) oxygen

Question 15.
The end product of photosynthesis is ……………………
(a) glucose
(b) sucrose
(c) fructose
(d) none of the above
Answer:
(a) glucose

Samacheer Kalvi 9th Science Guide Chapter 20 Organ Systems in Animals

II. Fill in the blanks :

1. The minerals like nitrogen, potassium and phosphorus, are required in substantial quantity by the plants are called …………………..
Answer:
macronutrients

2. The solar tracking of sunflower in accordance with the path of sun is due to ………………………
Answer:
phototropism

3. The response of a plant part towards gravity is ………………………
Answer:
geotropism

4. When the leaves of a sensitive plant are touched with a finger, they fold up and when light fades at dusk the petals of a sunflower. These two plants show ……………………..and ……………………..movements.
Answer:
thigmonastic, photonastic

Samacheer Kalvi 9th Science Guide Chapter 20 Organ Systems in Animals

5. Opening and closing of Moon flower is not a tropism because the movement in this is……………………..
Answer:
independent of stimulus

6. The raw materials for photosynthesis are …………………….. and ………………………
Answer:
carbon dioxide, water

7. When iodine solution is added for testing starch, part of the leaf with …………………….. turn blue- black colour.
Answer:
starch

8. In leaves, the food is stored in the form of……………………..
Answer:
starch

9. Plants may inhale carbon dioxide for photosynthesis but need ……………………..for their living.
Answer:
oxygen

10. Plants utilize only ……………………..% of the absorbed water for photosynthesis and the other activities.
Answer:
1

Samacheer Kalvi 9th Science Guide Chapter 20 Organ Systems in Animals

11 . Plants inhale and exhale continuously through the . ……………………..
Answer:
stamata

12. The bending of shoot towards light is due to the hormone ……………………..
Answer:
auxin

13. Heliotropism is a kind of ……………………..
Answer:
phototropism

14. The ……………………..plant exhibits one of the fastest known nastic movements.
Answer:
venus flytrap

15. Chlorophyll differs from haemoglobin by the presence of its central molecule ……………………..
Answer:
magnesium

16. Plants exchange gases ……………………..continuously through these stomata.
Answer:
CO2 to O2

17. Guard cells help in regulating the ……………………..
Answer:
rate of transpiration

Samacheer Kalvi 9th Science Guide Chapter 20 Organ Systems in Animals

III. Analogy :

Question 1.
Towards a stimulus : ……………….:: Away from the stimulus : Negative tropism
Answer:
Positive tropism

Question 2.
Hydrotropism : Response towards water :: Phototropism : …………..
Answer:
Response towards light

Question 3.
Photosynthesis : ……………….. :: Transpiration : Stomata
Answer:
Green leaves

Samacheer Kalvi 9th Science Guide Chapter 20 Organ Systems in Animals

IV. State whether the following statements are true or false. If false, write the correct statement :

1. Scientific term used to represent the bending of roots towards water is called geotropism.
Answer:
False.
Correct statement: Scientific term used to represent the bending of roots towards water is called hydrotropism.

2. When the leaves of Mimosa pudica plant are touched with the finger, they fold up quickly.
Answer:
True.
Correct statement: This is an example of thigmonasty.

3. The petals of moon flower open up in morning and closes in the evening. This is called photonasty.
Answer:
False.
Correct statement :The petals of moon flower dost ‘ in the morning and opens up in the evening. This is called photonasty.

Samacheer Kalvi 9th Science Guide Chapter 20 Organ Systems in Animals

4. Photosynthesis produces glucose and carbon dioxide.
Answer:
False.
Correct statement: Photosynthesis produces glucose and oxygen.

5. Photosynthesis is important in releasing oxygen to keep the atmosphere in balance.
Answer:
True.

6. Plants lose water when the stomata on leaves are closed.
Answer:
False.
Correct statement: Plants will not lose water when the stomata on leaves are closed.

V. Assertion and reason :

Question 1.
Assertion (A) : If the plant part moves in the direction of gravity, it is called positive geotropism.
Reason (R) : Stem shows positive geotropism.
(a) A and R are incorrect
(b) A is incorrect, R is correct
(c) A is correct, R is incorrect
(d) Both A and R are correct
Answer:
(c) A is correct, R is incorrect

Question 2.
Assertion (A) : The loss of excess water from the aerial parts of the plant in the form of water vapour is known as transpiration.
Reason (R) : Stomata of the leaf perform transpiration.
(a) A and R are incorrect
(b) A is incorrect, R is correct
(c) A is correct, R is incorrect
(d) Both A and R are correct
Answer:
(d) Both A and R are correct

Samacheer Kalvi 9th Science Guide Chapter 20 Organ Systems in Animals

VI. Short answer questions :

Question 1.
Write the scientific terms used to represent the following:
(a) Growing of roots towards the gravity.
(b) Bending of roots towards the water.
Samacheer Kalvi 9th Science Guide Chapter 19 Plant Physiology 6
Answer:
(a) Positive geotropism
(b) Positive hydrotropism.

Samacheer Kalvi 9th Science Guide Chapter 20 Organ Systems in Animals

Question 2.
Observe the given picture.
(a) Identify this plant. What type of special movement is shown by this plant?
(b) What are the other movements seen in this plant?
Answer:
(a) Mimosa pudica.
Special movement shown by the plant: Just a casual touch is enough to make the leaves of Mimosa pudica (Touch-me- not plant) fold up and droop. This is described as seismonasty or thigmonasty.
Movements which are not directed towards stimuli but are independent of the stimulus direction are called as nastie movements. They may or may not be growth movement.

(b) The foliage of Mimosa closes during darkness and reopens in the presence of light. Note : The ‘rapid movement of in leaflets in Mimosa is rare in the plant kingdom and is related to changes in turgor pressure.

Question 3.
What is the end product of photosynthesis?
Answer:
The end product of photosynthesis is glucose which is converted into starch and stored in the plant parts.

Question 4.
Name the minute openings seen on the lower surface of the leaf.
Answer:
Stomata are the minute openings seen on the lower surface of the leaf.

Samacheer Kalvi 9th Science Guide Chapter 20 Organ Systems in Animals

Question 5.
Give the scientific terms for the following:
(a) Growth dependent movement in plants.
(b) Growth independent movement in plants.
Answer:
(a) Tropic movements
(b) Nastie movements.

Question 6.
Study the pictures below and then complete the table by putting a plus (+) if the shoot or root grows towards the stimulus and a minus (-) if it grows away from it.
Samacheer Kalvi 9th Science Guide Chapter 19 Plant Physiology 7
Samacheer Kalvi 9th Science Guide Chapter 19 Plant Physiology 8
Answer:
Samacheer Kalvi 9th Science Guide Chapter 19 Plant Physiology 9

Question 7.
What is the other name for thigmonasty?
Answer:
Seismonasty.

Question 8.
Which flowering plant shows photonasty just opposite to that of Dandelion?
Answer:
Moon flower.

Samacheer Kalvi 9th Science Guide Chapter 20 Organ Systems in Animals

Question 9.
Give an example for negative hydrotropism.
Answer:
Growth of certain fungal hyphae away from the source of water/moisture.
Note : No clear evidences of negative hydrotropism.

Question 10.
Which gas is evolved during photosynthesis?
Answer:
Oxygen.

Question 11.
Give an example for micronutrients.
Answer:
Zinc.

Question 12.
What does a Mimosapudica plant do in response to touch? What is the phenomenon known as?
Answer:
In response to touch, the leaves of the plant Mimosa pudica fold up and droop. The movement is known as seismonasty or thigmonasty.

Samacheer Kalvi 9th Science Guide Chapter 20 Organ Systems in Animals

Question 13,
(i) What happens to the dandelion flower
(a) During the daytime?
(b) At night?
(ii) What is the phenomenon known as?
Answer:
(i) (a) The dandelion flower unfolds.
(b) The dandelion flower closes.
(ii) The phenomenon is known as photonasty.

Question 14.
Define photosynthesis.
Answer:
‘Photo’ means Tight’ and ‘synthesis’ means ‘to build’ thus photosynthesis literally means ‘building up with the help of light’. During this process, the light energy is converted into chemical energy. Green plants are autotrophic in their mode of nutrition because they prepare their food materials through a process called photosynthesis.\

Question 15.
Draw the structure of stomata and label the parts.
Answer:
Samacheer Kalvi 9th Science Guide Chapter 19 Plant Physiology 10

Samacheer Kalvi 9th Science Guide Chapter 20 Organ Systems in Animals

Question 16.
Complete the following table with the different types of tropism:
Samacheer Kalvi 9th Science Guide Chapter 19 Plant Physiology 11
Answer:
Samacheer Kalvi 9th Science Guide Chapter 19 Plant Physiology 12

Question 17.
Label the diagram with the raw materials and products of photosynthesis.
Samacheer Kalvi 9th Science Guide Chapter 19 Plant Physiology 13
Answer:
A. Carbon dioxide
B. Water
C. Glucose
D. Oxygen

Samacheer Kalvi 9th Science Guide Chapter 20 Organ Systems in Animals

Question 18.
Give an example for the movement of plant part which is very quick and can be observed easily.
Answer:
Just a casual touch is enough to make the leaves of Mimosa pudica fold up and droop. This takes place quickly and can be easily observed.

Question 19.
Name the cell that surrounds the stoma.
Answer:
Guard cells.

Question 20.
Give an example for chemotropism.
Answer:
During fertilization, pollen tube grows down the style in response to the sugars in the style is an example of chemotropism.

Samacheer Kalvi 9th Science Guide Chapter 20 Organ Systems in Animals

Question 21.
Give the overall equation for photosynthesis.
Answer:
Samacheer Kalvi 9th Science Guide Chapter 19 Plant Physiology 14

Question 22.
Guard cells of stomata are green but cannot photosynthesize? Give reason.
Answer:
The enzymes needed for photosynthetic reactions are absent and hence guard cells cannot photosynthesize. _ .

Question 23.
Why do roots of halophytes show negative geotropism.
Answer:
The roots turn 180° upright for respiration.

Question 24.
Why do stems show postive phototropism?
Answer:

  • Stem growing up and towards light is more likely to get sunlight for photosynthesis and display its flowers prominently for pollinators to arrive.
  • It also has better chance of spreading its seeds.

Samacheer Kalvi 9th Science Guide Chapter 20 Organ Systems in Animals

Question 25.
Mention four factors required for photosynthesis?
Answer:
Chlorophyll, Water, Carbon dioxide and Light.

Question 26.
Why is transpiration called as necessary evil?
Answer:
Water is lost by transpiration but still it is a necessary process since it gives the following advantages to the plant.

  • Creates an absorption force in roots to suck more water form the soil.
  • Regulates the temperature of the plant. Hence transpiration is said to be a necessary evil.

Samacheer Kalvi 9th Science Guide Chapter 20 Organ Systems in Animals

Question 27.
What are stomata?
Answer:
The leaves have tiny holes, t ailed slomaia, through which the exchange of air takes place. The leaves have tiny, microscopic pores called stomata. Water evaporates through these stomata. Each stomata is surrounded by guard cells. These guard cells help in regulating the rate of transpiration by opening and closing of stomata.

Question 28.
Write the scientific terms used to represent.
Answer:
Leaves fold up and droop in touch-me-not plant Mimosa pudica Ans. Thigmonasty or Seismonasty.
Example: Brunnichia ovata and Mimosa pudica.

Samacheer Kalvi 9th Science Guide Chapter 20 Organ Systems in Animals

VII. Long answer questions :

Question 1.
Write a note on Transpiration.
Answer:

  • The loss of water in the form of wate r vapour from the aerial parts of the plant body is called as transpiration.
  • The leaves have tiny, microscopic pores called stomata.
  • Water evaporates through these stomata. Each stomata is surrounded by guard cells.
  • These guard cells help in regulating the rate of transpiration by opening and closing of stomata.

Question 2.
Write the types of tropism.
Answer:
Types of Tropism :
Based on the nature of stimuli, tropism can be classifi ed as follows.
Phototropism : Movement of a plant part towards light, e.g. shoot of a plant.
Geotropism : Movement of a plant in response to gravity, e.g. root of a plant.
Hydrotropism : Movement of a plant or part of a plant towards water, e.g root of a plant.
Thigmotropism : Movement of a plant part due to touch, e.g. climbing vines.
Chemotropism : Movement of a part of plant in response to chemicals, e.g growth of a pollen tube in response to sugar present on the stigma.

Tropism is generally termed positive if growth is towards the signal and negative if it is away from the signal. Shoot of a plant moves towards the light, the roots move away. Th us the shoots are positively phototropic.
Samacheer Kalvi 9th Science Guide Chapter 19 Plant Physiology 15
Usually shoot system of a plant is positively phototropic and negatively geotropic and root system is negatively phototropic and positively geotropic.
Samacheer Kalvi 9th Science Guide Chapter 19 Plant Physiology 16

Samacheer Kalvi 9th Science Guide Chapter 20 Organ Systems in Animals

VIII. Higher Order Thinking Skills :

Question 1.
While conducting experiments to study the effects of various stimuli on the plants, it was observed that the roots of a plant X grow and bend towards two stimuli A and B but bend away from a third stimulus C. The stem of the plant X however bends ” away from stimulus A and B but bends towards the stimulus C. The stimulus B is known to act on the roots due to factors related with Earth. Keeping these points in mind, answer the following questions:
(a) What could be stimulus A ?
(b) Name the stimulus seen in B.
(c) What could be stimulus-C?
Answer:
(a) Stimulus A – Water
(b) Stimulus B – Gravity
(c) Stimulus C – Light

Samacheer Kalvi 9th Science Guide Chapter 20 Organ Systems in Animals

Question 2.
An organism A which cannot move from one place to another makes a simple food B from the substances C and D available in the environment. This food is made in the presence of green coloured substance E present in organs F in the presence of light energy in a process called G. Some of the simple food B also gets converted into a complex food H for storage purposes. This food gives blue-black colour with iodine solution?
(a) What is (i) organism A (ii) food B and food H?
(b) What are C and D?
(c) Name (i) green coloured substance E and organ F.
(d) What is the process G?
Answer:
(a) (i) Organism A refers to Green plants.
(ii) Food B – Glucose
Food H – Starch

(b) C – Carbon dioxide
D – Water

(c) Green coloured substance E – Chlorophyll
Organ F – Leaves

(d) G – Photosynthesis process.

Samacheer Kalvi 9th Science Guide Chapter 20 Organ Systems in Animals

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9th Science Guide Organ Systems in Animals Text Book Back Questions and Answers

Samacheer Kalvi 9th Science Guide Chapter 20 Organ Systems in Animals

I. Choose the correct answer :

Question 1.
Which of the following is not a salivary gland?
(a) Sublingual
(b) Lachrymal
(c) Submaxillary
(d) Parotid
Answer:
(b) Lachrymal

Question 2.
Stomach of human beings mainly digests ……………….
(a) carbohydrates
(b) proteins
(c) fat
(d) sucrose
Answer:
(b) proteins

Samacheer Kalvi 9th Science Guide Chapter 20 Organ Systems in Animals

Question 3.
To prevent the entry of food into the trachea, the opening is guarded by ………………..
(a) epiglottis
(b) glottis
(c) hard palate
(d) soft palate
Answer:
(a) epiglottis

Question 4.
Bile helps in the digestion of ………………..
(a) proteins
(b) sugar
(c) fats
(d) carbohydrates
Answer:
(c) fats

Samacheer Kalvi 9th Science Guide Chapter 20 Organ Systems in Animals

Question 5.
The structural and functional unit of the kidney is ………………..
(a) villi
(b) liver
(c) nephron
(d) ureter
Answer:
(c) nephron

Question 6.
Which one of the following substance is not a constituent of sweat?
(a) Urea
(b) Protein
(c) Water
(d) Salt
Answer:
(b) Protein

Samacheer Kalvi 9th Science Guide Chapter 20 Organ Systems in Animals

Question 7.
The common passage meant for transporting urine and sperms in male is ………………..
(a) ureter
(b) urethra
(c) vas deferens
(d) scrotum
Answer:
(c) vas deferens

Question 8.
Which of the following is not a part of female reproductive system?
(a) Ovary
(b) Uterus
(c) Testes
(d) Fallopian tube
Answer:
(c) Testes

II. Fill in the blanks :

1. The opening of the stomach into the intestine is called …………………
Answer:
pylorus

Samacheer Kalvi 9th Science Guide Chapter 20 Organ Systems in Animals

2. The muscular and sensory organ which helps in mixing the food with saliva is ………………..
Answer:
tongue

3. Bile, secreted by liver is stored temporarily in………………..
Answer:
gall bladder

4. The longest part of alimentary canal is………………..
Answer:
ileum

5. The human body functions normally at a temperature of about …………………
Answer:
37°C

Samacheer Kalvi 9th Science Guide Chapter 20 Organ Systems in Animals

6. The largest cell in the human body of a female is………………..
Answer:
ovum

III. State whether true or false. If false, correct the statement.

1. Nitric acid in the stomach kills microorganisms in the food.
Answer:
False.
Correct statement : Hydrochloric acid in the stomach kills micro-organisms in the food.

2. During digestion, proteins are broken down into amino acids.
Answer:
True.

3. Glomerular filtrate consists of many substances like amino acids, vitamins, hormones, salts, glucose and other essential substances.
Answer:
False.
Correct statement: Hormones are not present in glomerular filtrate.

Samacheer Kalvi 9th Science Guide Chapter 20 Organ Systems in Animals

IV. Match the following :

Organ Elimination
1. Skin (a) Urine
2. Lungs (b) Sweat
3. Intestine (c) Carbon dioxide
4. Kidneys (d) Undigested food

Answer:
1 – b, 2 – c, 3 – d, 4 – a

V. Differentiate the following :

a. Excretion and Secretion
b. Absorption and Assimilation
c. Ingestion and Egestion
d. Diphyodont and Heterodont
e. Incisors and Canines
Answer:
(a) Excretion
The process of removal of nitrogenous wastes generated in the body is called excretion.

Samacheer Kalvi 9th Science Guide Chapter 20 Organ Systems in Animals

Secretion
A process by which substances are produced and discharged from a cell, gland or organ for a function in the organism or for excretion.

(b)
Absorption
Absorption is the process by which nutrients obtained after digestion are absorbed by villi and circulated

  1. throughout the body by blood and lymph and supplied to all body cells according to their requirements.
  2. It takes place in the small intestine. It

Assimilation :

  1. Assimilation means the incorporation of the absorbed food materials into the tissue cells as their internal and hoihogenous component.
  2.  takes place in the cells of the body.

(c) Ingestion
The process of nutrition begins with intake of food, called ingestion.

Egestion :
The undigested or unassimilated portion of the ingested food material is thrown out from the body through the anal aperture as faecal matter. This is known as egestion or defaecation.

(d) Diphyodont
In human beings two sets of teeth (Diphyodont) are developed in their life time. The first appearing set of 20 teeth ca! led temporary or milk teeth are replaced by the second set of thirty two permanent teeth, sixteen in each jaw. This is called Diphyodont dentition.

Heterodont
Permanent teeth are of four types according to their struture and function namely Incisors, Canines, Premolars and molars. This is called Heterodont dentition.

Samacheer Kalvi 9th Science Guide Chapter 20 Organ Systems in Animals

(e) Incisors  :

  1. Used for cutting and biting.
  2. In a human adult there are 8 incisors

Canines

  1. Used for tearing and piercing.
  2. In a human adult there are 4 canines.

VI. Answer briefly :

Question 1.
How is the small intestine designed to absorb digested food?
Answer:
Small intestine comprises three parts- duodenum, jejunum and ileum. Ileum is the longest part of the small intestine. It contains minute finger-like projections called villi where absorption of food takes place. They are approximately 4 million in number. Internally, each villus contains fine blood capillaries and lacteal tubes.

Question 2.
Why do we sweat?
Answer:
The human body functions normally at a temperature of about 37°C. When it gets hot sweat glands start secreting sweat, which contains water with small amounts of other chemicals like ammonia, urea, lactic acid and salts (mainly sodium chloride). The sweat passes through the pores in the skin and gets evaporated, which reduces the body temperature.

Samacheer Kalvi 9th Science Guide Chapter 20 Organ Systems in Animals

Question 3.
Mention any two vital functions of the human kidney.
Answer:
Two vital functions of the kidneys are;

  1. Maintain the fluid and electrolyte balance in our body.
  2. Maintain the osmotic pressure in blood and tissues.

Question 4.
What is micturition?
Answer:
When the urinary bladder is full the urine is expelled out through the urethra. This process is called micturition. A healthy person excretes one to two litres of urine per day.

Question 5.
Name the types of teeth present in an adult human being. Mention the functions of each.
Answer:
Permanent teeth are of four types (Heterodont), according to their structure and function namely incisors, canines, premolars, and molars.

Types of teeth and their functions :
Samacheer Kalvi 9th Science Guide Chapter 20 Organ Systems in Animals 1

Samacheer Kalvi 9th Science Guide Chapter 20 Organ Systems in Animals

Question 6.
Explain the structure of nephron.
Answer:
Samacheer Kalvi 9th Science Guide Chapter 20 Organ Systems in Animals 2

  • Each kidney consists of more than one million nephrons. Nephrons or uriniferous tubules are structural and functional units of the kidneys.
  • Each nephron consists of Renal corpuscle or Malphigian corpuscle and renal tubule.
  • The renal corpuscle consists of a cup-shaped structure called Bowman’s capsule containing a bunch of capillaries called glomerulus.
  • Blood enters the glomerular capillaries through afferent arterioles and leaves out through efferent arterioles.
  • The Bowman’s capsule continues as the renal tubule which consists of three regions proximal convoluted tubule, U-shaped hair pin loop, the loop of Henle and the distal convoluted tubule.
  • The distal convoluted tubule which opens into the collecting tubule. The nitrogenous wastes are drained into renal pelvis of kidney which leads to ureters and stored in the urinary bladder.
  • Urine is expelled out through the urethra.

Samacheer Kalvi 9th Science Guide Chapter 20 Organ Systems in Animals

VII. Answer in detail :

Question 1.
Describe the alimentary canal of man.
Answer:
Alimentary canal is a muscular coiled, tubular structure. It consists of mouth, buccal cavity, pharynx, oesophagus, stomach, small intestine (consisting of duodenum, jejunum and ileum), large intestine (consisting of caecum, colon and rectum) and anus.
Samacheer Kalvi 9th Science Guide Chapter 20 Organ Systems in Animals 3

Mouth: Leads into the buccal cavity. It is bound 2 soft movable upper and lower lips. The buccal cavity is a large space-bound above by the palate (which separates the windpipe and food tube), below by the throat and on the sides by the jaws. The jaws bear teeth.

Teeth: Hard structures meant
for holding, cutting, grinding and crushing the food. In human beings, two sets of teeth (Diphyodont) are developed in their lifetime.

Each tooth has a root fitted in the gum (Theocodont). Permanent teeth are of four types (Heterodont), according to their structure and function namely incisors, canines, premolars and molars.

Dental formula represents the number of different type of teeth present in each half of a jaw (upper and lower jaw).
For Permanent teeth in each half of upper and lower jaw:
\(\frac{2,1,2,3}{2,1,2,3}\) = 16 x 2 = 32

Samacheer Kalvi 9th Science Guide Chapter 20 Organ Systems in Animals

Salivary glands: There are 3 pairs

  • Parotid glands Largest salivary glands, which lie in the cheeks in front of the ears.
  • Sublingual glands Smallest lands and lie beneath the tongue.
  • Submaxillary or Submandibular-glands-lie at the angles of the lower jaw.

Tongue: Muscular, sensory organ – Helps in mixing the food with the saliva.

Pharynx: It is a membrane-lined cavity behind the nose and mouth, connecting them to the oesophagus. Serves as” a pathway for the movement of food from mouth to oesophagus.

Oesophagus: Muscular-membranous canal about 22 cm in length. It conducts food ‘ from pharynx to the stomach by peristalsis (wave-like movement) produced by the rhythmic contraction and relaxation of the muscular walls of alimentary canal.

Stomach: Wide J-shaped muscular organ located.

Location: Between oesophagus and the small intestine.

Small intestine: The small intestine is the longest part of the alimentary canal, which is a long coiled tube measuring about 5 – 7 m. It comprises three parts- duodenum, jejunum, and ileum.

  • Duodenum – C-shaped and receives the bile duct (from the liver) and pancreatic duct (from Pancreas). ’
  • Jejunum Middle part of the small intestine. A short region of the small intestine.
  • Ileum – Forms the lower part of the small intestine and opens into the large intestine.

Liver: Largest digestive gland of the body, reddish-brown in colour. Bile salts help in the digestion of fats by emulsification (conversion of large fat droplets into small ones).

Pancreas: Lobed, a leaf-shaped gland situated between the stomach and duodenum.
Pancreas acts both as an exocrine gland and as an endocrine gland.

Large intestine: The unabsorbed and undigested food is passed into the large intestine.
It extends from the ileum to the anus. About 1.5 meters in length. Has 3 parts colon and rectum.

Caecum: Small blind pouch-like structure at the junction of the small and large intestine.
From its blind end, a finger-like structure called a vermiform appendix arises. It is a vestigeal (functionless) organ in human beings.

Colon: Much broader than ileum. Passes up the abdomen on the right ascending colon,
crosses to the left just below the stomach (transverse colon) and down on the left side – (descending colon).

Rectum: Last part which opens into the anus muscles called mi;)! Spain opens when passing stools.

Samacheer Kalvi 9th Science Guide Chapter 20 Organ Systems in Animals

Question 2.
Explain the structure of the kidney and the steps involved in the formation of urine.
Answer:
STRUCTURE OF KIDNEYS:

  • Kidneys are bean-shaped reddish-brown in colour.
  • The kidneys lie on either side of the vertebral column in the abdominal cavity attached to the dorsal body wall.
  • The right kidney is placed lower than the left kidney as the liver takes up much space on the right side.
  • Each kidney is about 11 cm long, 5 cm wide, and 3 cm thick.
  • Internally the kidney consists of:
    • An outer dark region the cortex. Longitudinal section of human kidney
    • The inner lighter region the medulla.
  • Both of these regions contain uriniferous tubules or nephrons.
  • The medulla consists of multitubular conical masses called the
    or whose bases are adjacent to the cortex.
  • On the inner concave side of each kidney, a notch called hilum is present through which blood vessels and nerves enter in and the urine leaves out.
    Samacheer Kalvi 9th Science Guide Chapter 20 Organ Systems in Animals 4

STEPS INVOLVED IN URINE FORMATION :

There are three stages.

  1. Glomerular filtration
  2. Tubular reabsorption and
  3. Tubular secretion

Glomerular filtration: Urine formation begins with the filtration of blood through epithelial walls of the glomerulus and Bowman’s capsule. The filtrate is called the glomerular filtrate. Both essential and non-essential substances present in the blood are filtered.

Tubular reabsorption: The filtrate in the proximal tubule consists of essential substances such as glucose, amino acids, vitamins sodium-potassium bicarbonates, and water that are reabsorbed into the blood by a process of selective reabsorption

Tubular secretion: Substances such as EU or ions are secreted into the tubule. This tubular filtrate is finally known as urine , which is hypertonic in man Finally the urine passes into collecting ducts to the pelvis and through the ureter into the urinary bladder. When the urinary bladder is full the urine is expelled out through the urethra. This process is called micturition. The healthy person excretes 1-2 litres of urine/day.

Samacheer Kalvi 9th Science Guide Chapter 20 Organ Systems in Animals

VIII. Assertion and Reason :

Mark the correct answer as ;
a. If both Assertion and Reason are true and Reason is the correct explanation of Assertion.
b. If both Assertion and Reason are true but Reason is not the correct explanation of Assertion.
c. If Assertion is true but Reason is false.
d. If both Assertion and Reason are false.

Question 1.
Assertion: Urea is excreted out through the kidneys.
Reason: Urea is a toxic substance.
Answer:
(a) Both Assertion and Reason are true and Reason is the correct explanation of Assertion

Question 2.
Assertion: In both the sexes gonads perform dual function.
Reason: Gonads are also called primary sex organs.
Answer:
(a) Both Assertion and Reason are true and Reason is the correct explanation of Assertion

Samacheer Kalvi 9th Science Guide Chapter 20 Organ Systems in Animals

IX. Higher Order Thinking Skills :

Question 1.
If pepsin is lacking in gastric juice, then which event in the stomach will be affected?
a. digestion of starch into sugars.
b. breaking of proteins into peptides.
c. digestion of nucleic acids.
d. breaking of fats into glycerol and fatty acids.
Answer:
b. breaking of proteins into peptides.

Question 2.
Name the blood vessel that
(a) enter malphigian capsule and
(b) leaves malphigian capsule.
Answer:
(a) Afferent arteriole.
(b) Efferent arteriole.

Samacheer Kalvi 9th Science Guide Chapter 20 Organ Systems in Animals

Question 3.
Why do you think that urine analysis is an important part of medical diagnosis?
Answer:
Urine is excreted from the human body which constitutes more than 95% water and other constituents like urea, chloride, sodium, potassium, creatinine and other dissolved ions, and inorganic and organic compounds. When there is an illness or disease, the constituents and its levels in urine also change.

Therefore urinalysis is also an important diagnostic tool which may be used to screen for and/or help diagnose conditions such as urinary tract infections, kidney disorders, liver problems, diabetes, or other metabolic conditions.

Question 4.
Why does your doctor advise you to drink plenty of water?
Answer:
Drinking water helps

  • Maintain the balance of fluids and electrolytes in the body.
  • When muscle cells don’t get enough water it results in muscle fatigue.
  • The functioning of kidneys also requires a lot of water.
  • Staying hydrated is necessary for good health.

Question 5.
Can you guess why there are sweat glands on the palm of our hands and the soles of our feet?
Answer:
Sweating is important for thermal regulation. Sweat works as a defense against microbes to which our hands and feet are mostly exposed than the other parts of our body.

Samacheer Kalvi 9th Science Guide Chapter 20 Organ Systems in Animals

X. Match the parts of the given figure with the correct option:
Samacheer Kalvi 9th Science Guide Chapter 20 Organ Systems in Animals 5
Answer:
Samacheer Kalvi 9th Science Guide Chapter 20 Organ Systems in Animals 6

Intext Activities

ACTIVITY – 1

Look at the picture given below and answer the questions that follow :
Samacheer Kalvi 9th Science Guide Chapter 20 Organ Systems in Animals 7
1. Are the teeth of animals similar to ours?
2. How is the shape of their teeth related to their food habit?
Answer:
There are many differences between human teeth and animal teeth.

  • Humans have at most 32 teeth, but many animals have more than we do.
  • Humans use them for breaking down food but animals need these teeth for breaking down of food and also for survival such as hunting, attacking, and defending themselves.

Lion Teeth: They are
Carnivore Teeth: Teeth are very sharp and scissor-like. Their front teeth are used to bite and hold onto prey while their long canine teeth are used for tearing flesh and meat. Their molars are also sharp – and used for slicing rather than chewing because they mainly swallow their food in whole chunks.

Bison or buffalo teeth: They are
Herbivore teeth: An herbivore is an animal that gets energy from eating plants. Herbivores have more molars than we do. They use these flat teeth for grinding branches, grasses, and seeds. Since their food doesn’t try to escape, they use their front teeth like pruning shears to clip leaves and stems.

9th Science Guide Organ Systems in Animals Additional Important Questions and Answers

I. Choose the correct answers :

Question 1.
In the dental formula \(\frac{2,1,2}{2,1,2}\) 3 refers to ……………………
(a) incisors
(b) molars
(c) premolars
(d) canine
Answer:
(b) molars

Samacheer Kalvi 9th Science Guide Chapter 20 Organ Systems in Animals

Question 2.
Lysozyme is seen in …………………….
(a) gastric juice
(b) intestinal juice
(c) bile
(d) saliva
Answer:
(d) saliva

Question 3.
…………………… is the smallest gland.
(a) Pancreas
(b) Sublingual
(c) Parotid
(d) Submaxillary
Answer:
(b) Sublingual

Question 4.
Curdling of milk protein is done by ……………………
(a) pepsin
(b) rennin
(c) lipase
(d) maltase
Answer:
(b) rennin

Samacheer Kalvi 9th Science Guide Chapter 20 Organ Systems in Animals

Question 5.
……………………acts as birth canal.
(a) Fallopian tube
(b) Vagina
(c) Uterus
(d) Vasdeferens
Answer:
(b) Vagina

Question 6.
The act of bringing swallowed food back to the mouth
(a) egestion
(b) ingestion
(c) micturition
(d) regurgitation
Answer:
(d) regurgitation

Question 7.
Gastric glands do not secrete ……………………
(a) renin
(b) pepsin
(c) lipase
(d) none of the above
Answer:
(c) lipase

Samacheer Kalvi 9th Science Guide Chapter 20 Organ Systems in Animals

Question 8.
Excretion means …………………….
(a) taking in oxygen from the air and giving out carbon dioxide.
(b) disposal of harmful germs and worms from our body.
(c) distribution of digested food to the body tissues through blood.
(d) removal of nitrogenous wastes generated in the body.
Answer:
(d) removal of nitrogenous wastes generated in the body

Question 9.
Which is the major excretory product in human?
(a) H+ or K+
(b) Glucose
(c) Urea
(d) Creatinine
Answer:
(a) H+ or K+

Question 10.
Which is a pear-shaped muscular organ in females?
(a) Uterus
(b) Fallopian tubes
(c) Ovaries
(d) Vagina
Answer:
(a) Uterus

Samacheer Kalvi 9th Science Guide Chapter 20 Organ Systems in Animals

Question 11.
What is the other name of fallopian tubes?
(a) Ovaries
(b) Fimbriae
(c) Oviducts
(d) Ova
Answer:
(c) Oviducts

II. Fill in the blanks :

1. ……………… is the smallest cell in males.
Answer:
Sperm

2. Progesterone is secreted by………………
Answer:
corpus luteum

3. The oviducts are also known as ………………
Answer:
fallopian tubes

4. One mature ovum is released once in every……………… days.
Answer:
28

Samacheer Kalvi 9th Science Guide Chapter 20 Organ Systems in Animals

5. Beta cells of pancreas produce ………………
Answer:
insulin

6. Organs which are concerned with the formation, storage and elimination of urine constitute the ………………
Answer:
excretory system

7. In the process of urine formation, the maximum amount of water from the glomerular filtrate is reabsorbed in the ………………
Answer:
proximal convoluted tubule

8. ……………… receives the sperms, acts as birth canal during childbirth.
Answer:
Vagina

Samacheer Kalvi 9th Science Guide Chapter 20 Organ Systems in Animals

9. The narrower lower part of the uterus is ………………
Answer:
cervix

10. ……………… carries sperms to the seminal vesicles.
Answer:
Vas deferens

11. ……………… is the smallest cell in the male body.
Answer:
Sperm

12. The process of formation of sperms is known as ………………
Answer:
spermatogenesis

Samacheer Kalvi 9th Science Guide Chapter 20 Organ Systems in Animals

13. ……………… is the vestigeal organ in human.
Answer:
Vermiform appendix

14. ……………… acts as a thermoregulatory organ.
Answer:
Sorotum

15. Tubular filtrate finally known as………………
Answer:
urine

Samacheer Kalvi 9th Science Guide Chapter 20 Organ Systems in Animals

III. Match the following:

Ovaries Bean shape
Fallopian tubes Almond shape
Uterus Funnel – shape
Kidney Peas -shape

Answer:

Ovaries Bean shape
Fallopian tubes Almond shape
Uterus Funnel – shape
Kidney Peas -shape

IV. Answer the following in one or two sentences :

1. It conducts food from pharynx to stomach by peristalsis.
Answer:
Oesophagus.

Samacheer Kalvi 9th Science Guide Chapter 20 Organ Systems in Animals

2. Finger-like projections enhance the absorbing capacity of the small intestine.
Answer:
Villi.

3. The bunch of capillaries inside the Bowman’s capsule.
Answer:
Glomerulus.

4. Thin muscular tubes which carry urine from kidney to urinary bladder.
Answer:
Ureter.

Samacheer Kalvi 9th Science Guide Chapter 20 Organ Systems in Animals

5. Small sac-like muscular structures that enclose testes.
Answer:
Scrotal sacs.

V. Very short answer questions :

Question 1.
Name the salivary glands.
Answer:
3 pairs of salivary glands are present in the mouth cavity.
They are Parotid glands, sublingual glands, and submaxillary or submandibular glands.

Question 2.
What is chyme?
Answer:
The action of the gastric juice SSid churning of food in the stomach converts the bolus into a semi-digested food called chyme.

Samacheer Kalvi 9th Science Guide Chapter 20 Organ Systems in Animals

Question 3.
What are villi?
Answer:
Ileum is the longest part of the small intestine. It contains minute finger-like projections called villi. They help in the absorption of food.

Question 4.
Name the bile salts.
Answer:
Sodium glycolate and sodium tauraglycolate.

Question 5.
Name the bile pigments.
Answer:
Bilirubin and Biliviridin

Samacheer Kalvi 9th Science Guide Chapter 20 Organ Systems in Animals

Question 6.
What is heparin?
Answer:
It is an anticoagulant produced by the liver.

Question 7.
What are Islets of Langerhans?
Answer:
The endocrine cells of the pancreas are known as Islets of Langerhans and they produced the hormones – insulin and glucagon.

Question 8.
What is succus entericus?
Answer:
The intestinal glands secrete intestinal juice called succus entericus which contains enzymes like maltase, lactase, sucrase, lipase etc.

Samacheer Kalvi 9th Science Guide Chapter 20 Organ Systems in Animals

Question 9.
What is a vermiform appendix?
Answer:
It is a finger-like structure originating from the blind end of the caecum, is the alimentary canal of man. It is a vestigial organ (functionless organ).

Question 10.
What is the contribution of Joseph E. Murray in Nephrology?
Answer:
He performed the first successful kidney transplant operation.

Question 11.
What is parturition?
Answer:
Childbirth is called parturition.

Samacheer Kalvi 9th Science Guide Chapter 20 Organ Systems in Animals

VI. Short answer questions :

Question 1.
What is an artificial kidney?
Answer:
Dialysis or artificial kidney :
(i) When kidneys lose their filtering efficiency, excessive amounts of fluid and toxic waste accumulate in the body. This condition is known as kidney (renal) failure.
For this, an artificial kidney is used to filter the blood of the patient. The patient is said to be put on dialysis and the process of purifying blood by an artificial kidney is called hemodialysis.
(ii) When renal failure cannot be treated by drug or dialysis, the patients are advised for kidney transplantation.

Question 2.
Draw the human excretory system and label the parts.
Answer:
Samacheer Kalvi 9th Science Guide Chapter 20 Organ Systems in Animals 8

Samacheer Kalvi 9th Science Guide Chapter 20 Organ Systems in Animals

Question 3.
What are the end products of digestion of starch, proteins and fats respectively?
Answer:
Starch – Glucose
Proteins – Amino acids
Fats – Fatty acids and glycerol

Question 4.
What are the functions of the ovaries and uterus in the female reproductive system?
Answer:
Functions of ovaries :

  • The ovaries are the female gonads, which produce ova or the female gametes.
  • They also secrete the female sex hormones namely estrogen and progesterone.

Functions of the uterus :

  • Uterus is a pear-shaped muscular, hollow structure present in the pelvic cavity.
  • The development of foetus occurs inside the uterus.

Question 5.
Give reasons for the following
(a) Scrotum remains outside the body of human males.
(b) The wall of the stomach is not digested by its own enzyme.
Answer:
(a) The two testes lie in the respective scrotal sacs. The scrotum acts as a thermoregulatory organ and provides an optimum temperature for the formation of sperms. The sperms develop at a temperature of 1-3°C lower than the normal body temperature. Hence scrotum remains outside the body of human males.

(b) The wall of the stomach is protected by mucus. Hence the wall of the stomach is not digested by its own enzymes. Further the gastric enzyme pepsinogen is present only in inactive form and converted into active pepsin only when food enters the stomach.

Samacheer Kalvi 9th Science Guide Chapter 20 Organ Systems in Animals

Question 6.
What is homeostasis?
Answer:
The tendency of the body to seek and maintain a balance condition or equilibrium within its internal environment, even when faced with external challenges is called homeostasis.

Question 7.
Rearrange the jumbled sequence of the different parts of alimentary canal in proper sequence, (oesophagus, small intestine, stomach, large intestine, anus, mouth, rectum)
Answer:
Mouth, oesophagus, stomach, small intestine, large intestine, rectum, anus.

Question 8.
Select the substances given below that need to be excreted from the body, (urea, amino acids, carbon dioxide, uric acid, glucose)
Answer:
Urea and carbon dioxide

Samacheer Kalvi 9th Science Guide Chapter 20 Organ Systems in Animals

Question 9.
Rearrange the jumbled words and fill in the blanks in the following passage to make it a meaningful description.
The human urinary system consists of a pair of …….. ( nyedik), which form the urine; a pair of …….. (ertreu), which conduct the …….. (neuri) from kidneys to the …….. (naryuri drebdal) for storage of urine and a …….. (reuhrat) through which the urine is voided by bladder contractions.
Answer:
1. Kidney
2. Ureter
3. Urine
4. Urinary bladder
5. Urethra

Samacheer Kalvi 9th Science Guide Chapter 20 Organ Systems in Animals

VII. Long answer questions :

Question 1.
List the function of the liver.
Answer:

  • Synthesizes foetal red blood cells.
  • Produces fibrinogen and prothrombin, used for clotting of blood.
  • Destroys red blood cells.
  • Stores iron, copper, vitamins A, and D.
  • Produces heparin (an anticoagulant).
  • Excretes toxic and metallic poisons.
  • Detoxifies substances including drugs and alcohol.

Question 2.
Draw a chart to show the various enzymes produced during digestion in our body and their action.
Answer:
Samacheer Kalvi 9th Science Guide Chapter 20 Organ Systems in Animals 9

Samacheer Kalvi 9th Science Guide Chapter 20 Organ Systems in Animals

Question 3.
Write a note on teeth of humans.
Answer:

  • Teeth are hard structures meant for holding, cutting, grinding, and crushing the food.
  • In human beings, two sets of teeth (Diphyodont) are developed in their lifetime. The first appearing set of 20 teeth called temporary or milk teeth are replaced by the second set of thirty-two permanent teeth, sixteen in each jaw. Each tooth has a root fitted in the gum (Theocodont).
  • Permanent teeth are of four types (Heterodont), according to their structure and function namely incisors, canines, premolars, and molars.
  • Dental formula represents the number of different types of teeth present in each half of a jaw (upper and lower jaw).
  • The types of teeth are denoted as incisors (i), canine (c), premolars (pm) and molars (m). The dental formula is presented as:

For Milk teeth in each half of upper and lower jaw:
\(\frac{2,1,2}{2,1,2}\)= 10 x 2 = 20
For Permanent teeth in each half of upper and lower jaw:

\(\frac{2,1,2,3}{2,1,2,3}\) = 16 x 2 = 32
Types of teeth and their functions

Samacheer Kalvi 9th Science Guide Chapter 20 Organ Systems in Animals 10

Samacheer Kalvi 9th Science Guide Chapter 20 Organ Systems in Animals

Question 4.
Write a note on functions of liver in digestion.
Answer:

  • It is the largest digestive gland of the body which is reddish-brown in colour.
  • It is divided into two main lobes, right and left lobes. The right lobe is larger than the left lobe.
  • On the undersurface of the liver, gall bladder is present. The liver cells secrete bile which is temporarily stored in the gall bladder.
  • Bile is released into small intestine when food enters in it. It has bile salts (sodium glycolate and sodium tauraglycolate) and bile pigments (bilirubin and biliviridin).
  • Bile ssfits help in the digestion of fats by bringing about their emulsification (conversion of large fat droplets into small ones).

Question 5.
Write a note on the skin.
Answer:

  • Skin is the outermost covering of the body. It stretches all over the body in the form of a layer.
  • It accounts for 15% of an adult’s human body weight. There are many structures and glands derived from the skin. It eliminates metabolic wastes through perspiration.
  • The human body functions normally at a temperature of about 37 C.
  • When it gets hot sweat glands to start secreting sweat, which contains water with small amounts of other chemicals like ammonia, urea, lactic acid and salts (mainly sodium chloride).
  • The sweat passes through the pores in the skin and gets evaporated.

VIII. Higher Order Thinking Skills :

Question 1.
Reproductive organs are also considered endocrine glands.
Answer:
The testes apart from producing sperms also produce male sex hormones called testosterone. Similarly, the ovary apart from producing the ovum also produces the female sex hormone called oestrogen. Hence the gonads are also considered endocrine glands.

Samacheer Kalvi 9th Science Guide Chapter 20 Organ Systems in Animals

Question 2.
Skin is considered to be an excretory organ – Justify.
Answer:
Skin eliminates

Samacheer Kalvi 9th Science Guide Chapter 21 Nutrition and Health

Tamilnadu State Board New Syllabus Samacheer Kalvi 9th Science Guide Pdf Chapter 21 Nutrition and Health Text Book Back Questions and Answers, Notes.

Tamilnadu Samacheer Kalvi 9th Science Solutions Chapter 21 Nutrition and Health

9th Science Guide Nutrition and Health Text Book Back Questions and Answers

Samacheer Kalvi 9th Science Guide Chapter 21 Nutrition and Health

I. Choose the correct answer :

Question 1.
The nutrient required in trace amounts to accomplish various body functions is ……………….
(a) carbohydrate
(b) protein
(c) vitamin
(d) fat
Answer:
(c) Vitamin

Samacheer Kalvi 9th Science Guide Chapter 21 Nutrition and Health

Question 2.
The physician who discovered that scurvy can be cured by ingestion of citrus fruits is ………………..
(a) James Lind
(b) Louis Pasteur
(c) Charles Darwin
(d) Isaac Newton
Answer:
(a) James Lind

Question 3.
The sprouting of onion and potatoes can be delayed by the process of ……………..
(a) freezing
(b) irradiation
(c) salting
(d) canning
Answer:
(b) Irradiation

Question 4.
Food and Adulteration Act was enforced by Government of India in the year …………..
(a) 1964
(b) 1954
(c) 1950
(d) 1963
Answer:
(b) 1954

Samacheer Kalvi 9th Science Guide Chapter 21 Nutrition and Health

Question 5.
An internal factor responsible for spoilage of food is …………………
(a) wax coating
(b) contaminated utensils
(c) moisture content in food
(d) synthetic preservatives
Answer:
(c) moisture content in food

II. Fill in the blanks :

1. Deficiency diseases can be prevented by taking ……………………… diet.
Answer:
balanced

Samacheer Kalvi 9th Science Guide Chapter 21 Nutrition and Health

2. The process of affecting the natural composition and the quality of food substance is
known as ………………………
Answer:
adulteration

3. Vitamin D is called as ……………………… vitamin as it can be synthesised by the body from the rays of sunlight.
Answer:
sunshine

4. Dehydration is based on the principle of removal of ………………………
Answer:
water

5. Food should not be purchased beyond the date of ………………………
Answer:
expiry

6. AGMARK is used to certify ……………………… and ……………………… products in India.
Answer:
agricultural, Livestock

Samacheer Kalvi 9th Science Guide Chapter 21 Nutrition and Health

III. State whether true or false. If false, correct the statement.

1. Iron is required for the proper functioning of thyroid gland.
Answer:
False.
Correct statement: Iodine is required for the proper functioning of the thyroid gland.

2. Vitamins are required in large quantities for normal functioning of the body.
Answer:
False.
Correct statement: Vitamins are required in minute quantities for normal functioning of the body.

Samacheer Kalvi 9th Science Guide Chapter 21 Nutrition and Health

3. Vitamin C is a water soluble vitamin.
Answer:
True.

4. Lack of adequate fats in diet may result in low body weight.
Answer:
True.

5. ISI mark is mandatory to certify agricultural products.
Answer:
False.
Correct statement: ISI mark is mandatory to certify Industrial products.

Samacheer Kalvi 9th Science Guide Chapter 21 Nutrition and Health

IV. Match the following :

Column A Column B
1. Calcium a. Muscular fatigue
2. Sodium b. Anaemia
3. Potassium c. Osteoporosis
4. Iron d. Goitre
5. Iodine e. Muscular cramps

Answer:
1-c, 2-e, 3 -a, 4-b

V. Fill in the blanks with suitable answers :

Vitamins Rich source Deficiency disease
Calciferol Rickets
Papaya Night blindness
Ascorbic acid
Whole grains Beriberi

Answer:

Vitamins Rich source Deficiency disease
Calciferol Liver, Dairy products, Fish Rickets
Retinol Papaya Night blindness
Ascorbic acid Leafy vegetables, Sprouts Citrus fruits Scurvy
Thiamine Whole grains Beriberi

Samacheer Kalvi 9th Science Guide Chapter 21 Nutrition and Health

VI. Give abbreviations for the following food standards :

  1. ISI ……………..
  2. FPO ……………..
  3. AGMARK ……………..
  4. FCI ……………..
  5. FSSAI ……………..

Answer:

  1. Indian Standards Institution.
  2. Fruit Process Order.
  3. Agricultural Marking.
  4. Food Corporation of India.
  5. Food Safety and Standards Authority of India.

VII. Assertion and Reason:

Direction: In the following question, a statement of an Assertion is given and a corresponding Reason is given just below it. Of the statements given below, mark the correct answer is:
(a) If both Assertion and Reason are true and the Reason is the correct explanation of Assertion
(b) If both Assertion and Reason are true but Reason is not the correct explanation of Assertion
(c) If Assertion is true but Reason is false
(d) If both Assertion and Reason is false

Question 1.
Assertion: Haemoglobin contains iron.
Reason: Iron deficiency leads to anemia.
Answer:
(b) Both Assertion and Reason are true but Reason is not the correct explanation of Assertion

Samacheer Kalvi 9th Science Guide Chapter 21 Nutrition and Health

Question 2.
Assertion: AGMARK is a quality control agency.
Reason: ISI is a symbol of quality.
Answer:
(d) Both Assertion and Reason is false

VIII. Give reasons for the following statements

a. Salt is added as a preservative in pickles …………………….
b. We should not eat food items beyond the expiry date …………………….
c. Deficiency of calcium in the diet leads to poor skeletal growth …………………….
Answer:
(a) Because it removes the moisture content in the food by osmosis.
(b) Because it will get spoilt and can cause diseases.
(c) Because calcium is a constituent of bones.

Samacheer Kalvi 9th Science Guide Chapter 21 Nutrition and Health

IX. Answer briefly:

Question 1.
Differentiate
a) Kwashiorkar from Marasmus
b) Macronutrients from Micronutrients
Answer:
(a)

Kwashiorkar Marasmus
1. Children whose diet mainly consists of carbohydrates but lack in protein. Children are affected when the diet is poor in carbohydrates, fats and proteins.
2. It affects children between 1-5 years of age It usually affects the intacts below the age of one year.

(b)
Answer:

Macronutrients Micronutrients
1. Nutrients required for the growth and development of the body in large quantities are called Macronutrients. Nutrients required for the growth and development of the body in small quantities are called Micronutrients.
2. Eg: Calcium, Potassium and Sodium. Eg: Iron and Iodine.

Samacheer Kalvi 9th Science Guide Chapter 21 Nutrition and Health

Question 2.
Why salt is used as a preservative in food?
Answer:

  1. It removes the moisture content in the food.
  2. Prevents the growth of bacteria.
  3. Reduces the activity of microbial enzymes.

Question 3.
What is an adulterant?
Answer:
Adulteration is defined as “the addition or subtraction of any substance to or from food so that the natural composition and the quality of food substance is affected.” The adulterant is any material which is used for the purpose of adulteration.

Question 4.
Name any two naturally occurring toxic substances in food.
Answer:
Alkaloids and Aflatoxin.

Question 5.
What factors are required for the absorption of Vitamin D from the food by the body?
Answer:

  1. Human skin can synthesize Vitamin D when exposed to sunlight (especially early morning).
  2. When the sun rays fall on the skin dehydro cholesterol is converted into Vitamin D. Hence, Vitamin D is called “Sunshine vitamin”.

Samacheer Kalvi 9th Science Guide Chapter 21 Nutrition and Health

Question 6.
Write any one function of the following minerals
a) Calcium
b) Sodium
c) Iron
d) Iodine
Answer:

Minerals Function
a. Calcium 1. Constituent of bones and enamel of teeth.
2. Controls muscle contraction.
b. Sodium 1. Maintains fluid balance.
2. Helps in neurotransmission.
c. Iron 1. Important component of hemoglobin.
d. Iodine 1. Necessary for the formation of thyroid hormone.

Question 7.
Explain any two methods of food preservation.
Answer:

  • SMOKING: Food products like Meat and Fish are exposed to smoke. The drying action of the smoke tends to preserve the food.
  • Use of Inert gas: Nitrogen gas is filled in air tight packets of Potato wafers and other products. It prevents the growth of fungus and insects in them.

Samacheer Kalvi 9th Science Guide Chapter 21 Nutrition and Health

Question 8.
What are the effects of consuming adulterated food?
Answer:
Consumption of these adulterated foods may lead to serious health issues like fever, diarrhoea, nausea, vomiting, gastrointestinal disorders, asthma, allergy, neurological disorder, skin allergies, immune suppression, kidney and liver failure, colon cancer, and even birth defects.

X. Answer in detail :

Question 1.
How are vitamins useful to us? Tabulate the sources, deficiency diseases and symptoms of fat soluble vitamins.
Answer:
Samacheer Kalvi 9th Science Guide Chapter 21 Nutrition and Health 1
Samacheer Kalvi 9th Science Guide Chapter 21 Nutrition and Health 2

Question 2.
Explain the role of food control agencies in India.
Answer:
Food quality control agencies :
ISI, AGMARK, FPO, FCl and other health departments enforce minimum standards for the consumer products. FCI (Food Corporation of India) was set up in the year 1965 with the following objectives : ^

  • Effective price support operations for safeguarding the interest of farmers.
  • Distributing food grains throughout the country.
  • Maintaining satisfactory levels of operational and buff er stock of food grains to ensure national security.
  • Regulate the market price to provide food grains to consumers at reliable price.
Food control agency Role
1. ISI (Indian Standards
Institution) known as Bureau of Indian Standard (BIS)
Certifies industrial products like electrical appliances like switches, wiring cables, water heater, electric motor, kitchen appliances etc.
2. AGMARK (Agricultural Marking) Certifies agricultural and livestock products li ke cereals, essential oils, pulses, honey, butter etc.
3. FPO (Fruit Process Order) Certifies the fruit products like juice, jams, sauce, canned fruits and vegetables, pickles etc.,
4. Food Safety and Standards Authority of India. Responsible for protecting and promoting the public health through regulation and supervision of food safety

Samacheer Kalvi 9th Science Guide Chapter 21 Nutrition and Health

XI. Higher Order Thinking Skills :

Question 1.
Look at the picture and answer the question that follows.
Samacheer Kalvi 9th Science Guide Chapter 21 Nutrition and Health 3
a) Name the process involved in the given picture.
b) Which diary food is preserved by this process?
c) What is the temperature required for the above process?
Answer:
(a) Pasteurization.
(b) Milk.
(c) 63°C for 30 minutes followed by sudden cooling.

Samacheer Kalvi 9th Science Guide Chapter 21 Nutrition and Health

Question 2.
The doctor advices an adolescent girl who is suffering from anaemia to include more leafy vegetables and dates in her diet; Why so?
Answer:
Iron deficiency is the most common nutrient deficiency in adolescent girls. Insufficient iron can lead to anaemia. Leafy vegetables and dates are rich in iron and other minerals. So the doctor advises to include more of these in the diet.

Question 3.
Sanj ana wants to buy an aim bottle in a grocery shop. What are the things she should observe on the label before purchasing it?
Answer:
She must look for the following details on the label of the jam bottle.

  • Date of manufacture and date of expiry. She must make sure that the contents of the bottle must be conserved before the date of expiry.
  • She must look for the FPO certification to ensure that the product has been certified by the quality agency and is safe for consumption.

9th Science Guide Nutrition and Health Additional Important Questions and Answers

I. Choose the best answers:

Question 1.
The maximum amount of energy provided by carbohydrate is …………………….
(a) 3 kcal
(b) 4 kcal
(c) 5 kcal
(d) 9 kcal
Answer:
(b) 4 kcal

Samacheer Kalvi 9th Science Guide Chapter 21 Nutrition and Health

Question 2.
……………….. is a polysaccharide.
(a) Glucose
(b) Sucrose
(c) Fructose
(d) Cellulose
Answer:
(d) Cellulose

Question 3.
There are ………………. essential amino acids required by the human body through the diet.
(a) 8
(b) 5
(c) 9
(d) 12
Answer:
(c) 9

Samacheer Kalvi 9th Science Guide Chapter 21 Nutrition and Health

Question 4.
…………………… is a trace element required by our body.
(a) Magnesium
(b) Iron
(c) Phosphorous
(d) Sodium
Answer:
(b) Iron

Question 5.
Pellagra is a deficiency disease, choose the vitamin related to it.
(a) Pyridoxine
(b) Cyanacobalamine
(c) Niacin
(d) Riboflavin
Answer:
(c) Niacin

Question 6.
Seafood is a source of …………………
(a) calcium
(b) potassium
(c) iodine
(d)chlorine
Answer:
(c) iodine

Question 7.
World Health Day is celebrated on ……………….
(a) 8th April
(b) 7th April
(c) 5th April
(d) 4th April
Answer:
(b) 7th April

Samacheer Kalvi 9th Science Guide Chapter 21 Nutrition and Health

Question 8.
World Food Day is celebrated on ………………
(a) 15th October
(b) 18th October
(c) 16th October
(d) 20th October
Answer:
(c) 16th October

Question 9.
Calcium carbide is used to ………………….
(a) Given colour to fruits
(b) Preserve Jams/Jellies
(c) Ripen bananas
(d) Adulterant in poultry feed
Answer:
(c) Ripen bananas

Samacheer Kalvi 9th Science Guide Chapter 21 Nutrition and Health

Question 10.
…………….. is an intentionally added adulterant in milk.
(a) Citric acid
(b) Hydrogen peroxide
(c) Starch
(d) Sucrose
Answer:
(b) Hydrogen peroxide

II. Fill in the blanks :

1. …………….. is an example of a monosaccharide.
Answer:
glucose

2. The lipids can provide a maximum of …………… of energy.
Answer:
9 kcal/gram

Samacheer Kalvi 9th Science Guide Chapter 21 Nutrition and Health

3. The term vitamin was introduced by ………..
Answer:
Dr. Funk

4. Swollen and bleeding gums is a symptom of _______
Answer:
scurvy

5. Delayed blood clotting is a symptom of deficiency of vitamin ______ in the body.
Answer:
K

6. Give an example of a substance used to protect food grains in the olden days
Answer:
Dried neem leaves/Turmeric

Samacheer Kalvi 9th Science Guide Chapter 21 Nutrition and Health

7. Smoking is a method of food preservation used for ……………
Answer:
meat/fish

8. The gas ……………. is filled in airtight packets of potato wafers.
Answer:
nitrogen

9. …………….. is a natural preservative used to increase the shelf life of fruit juices/squash.
Answer:
Sugar/Honey

Samacheer Kalvi 9th Science Guide Chapter 21 Nutrition and Health

III. Mention whether the following statements are true or false. If false, give the correct statements :

1. Carnauba wax is coated on apples to increase the taste.
Answer:
False.
Correct statement: Carnauba wax is coated on apples to give a shiny appearance.

2. Coffee power adulterated with tamarind powder floats in water.
Answer:
False.
Correct statement: Coffee powder adulterated with tamarind powder will not float but it will settle down at the bottom of the container.

3. Chalk powder is an adulterant used in common salt.
Answer:
True.

Samacheer Kalvi 9th Science Guide Chapter 21 Nutrition and Health

4. Louis Pasteur developed vaccination against Rabies and Anthrax.
Answer:
True.

5. In a food pyramid, fat and oil are placed at the bottom.
Answer:
False.
Correct statement: In a food pyramid, fat and oil are placed at the top of the pyramid

IV. Match the following :

1. Vacuum drying a. Vegetables
2. Cold storage b. Seeds
3. Deep freezing c. Cheese powder
4. Canning d. Meat

Answer:
1-c, 2 – a, 3-b, 4-d

Samacheer Kalvi 9th Science Guide Chapter 21 Nutrition and Health

V. Assertion and Reason :

Question 1.
Assertion (A): Bananas are kept at room temperature.
Reason (R): In a refrigeration-bananas ripen fast.
(a) A and R are incorrect.
(b) A is correct and R is the explanation for A.
(c) A is correct but R is not the correct explanation.
(d) A is correct and R is wrong.
Answer:
(d) A is correct and R is wrong

Samacheer Kalvi 9th Science Guide Chapter 21 Nutrition and Health

Question 2.
Assertion (A): Fruits and vegetables are placed at the bottom of a food pyramid.
Reason (R): They must be consumed in more quantities for good health.
(a) A and R are incorrect.
(b) A is correct and R is the explanation for A.
(c) A is correct and R is incorrect.
(d) A is incorrect R is correct.
Answer:
(b) A is correct and R is the explanation for A

VI. Analogy :

Question 1.
(a) Vitamin A : ……………
(b) …………… : Sterility in rats.
Answer:
(a) Nyctalopia
(b) Vitamin E

Samacheer Kalvi 9th Science Guide Chapter 21 Nutrition and Health

Question 2.
(a) …………… : Anaemia
(b) Iodine : …………….
Answer:
(a) Iron
(b) Goitre

Question 3.
(a) Jams : ……………
(b) …………… : oil.
Answer:
(a) Honey
(b) Pickles.

VII. Answer the following in one or two sentences:

Question 1.
Name any two essential amino acids.
Answer:
Phenylalanine and lysine.

Samacheer Kalvi 9th Science Guide Chapter 21 Nutrition and Health

Question 2.
Name the major minerals required by the human body.
Answer:
Calcium, phosphorous, potassium, sodium, and magnesium.

Question 3.
Give two examples of trace elements required by the body.
Answer:
Iron, chlorine.

Question 4.
Name the processes involved in metabolism.
Answer:
Anabolism and catabolism.

Question 5.
What is a balanced diet?
Answer:
A diet containing essential nutrients in the right proportion (balanced diet) is required for normal growth and development and to prevent malnutrition.

Question 6.
Give examples of synthetic food preservatives.
Answer:
Citric acid, vinegar.

Samacheer Kalvi 9th Science Guide Chapter 21 Nutrition and Health

Question 7.
How are adulterants classified?
Answer:

  • Natural adulterants
  • Incidental/unintentionally added adulterants.
  • Intentionally added adulterants.

Question 8.
Name the adulterants used in
(a) Tea leaves
(b) Chilli powder.
Answer:
(a) Coal tar dye
(b) Brick powder

VIII. Short answer questions :

Question 1.
What is goiter?
Answer:
It is a swelling of the region below the neck due to the enlargement of the thyroid gland. It is caused due to iodine deficiency.

Question 2.
Why do we need to preserve food?
Answer:

  • Increase the shelf life of food.
  • Retain the colour, texture, flavour and nutritive value.
  • Increase food supply.
  • Decrease the wastage of food.

Samacheer Kalvi 9th Science Guide Chapter 21 Nutrition and Health

Question 3.
What is pasteurization?
Answer:

  • Pasteurization is a process of heat treatment of liquid products. E.g for the preservation of milk and beverages.
  • This process also involves boiling of milk to a temperature of 63 °C for about 30 minutes and suddenly cooling to destroy the microbes present in the milk.

Question 4.
Why do we store bananas at room temperature?
Answer:
If bananas are kept in the refrigerator, the enzyme responsible for ripening becomes inactive. The enzyme responsible for browning and cell damage becomes more active and the skin colour changes to dark brown.

Question 5.
Why is the oil used as a preservative for pickles?
Answer:
The addition of oil in pickles prevents the contact of air with food. Hence microorganisms cannot grow and spoil the food.

Samacheer Kalvi 9th Science Guide Chapter 21 Nutrition and Health

Question 6.
List the methods of food preservation.
Answer:

  • Drinking
  • Smoking
  • Irradiation
  • Cold storage
  • Freezing
  • Pasteurization
  • Canning.

Question 7.
Why is sugar used to preserve fruits and fruit products?
Answer:
The hygroscopic nature of sugar/ honey helps in reducing the water content of food and also minimizing the process of oxidation in fruits.

Samacheer Kalvi 9th Science Guide Chapter 21 Nutrition and Health

Question 8.
Give a simple technique to detect adulteration in milk.
Answer:
Place a drop of milk on a slanting polished surface. Pure milk flows slowly leaving a trail behind while the milk adulterated with water will flow fast without leaving a trail. This is the single technique to detect adulteration in milk.

IX. Long answer questions:

Question 1.
Write a note on food preservatives.
Answer:
Food can be preserved by adding natural and synthetic preservatives.
A. Natural preservatives:
Some naturally available materials like salt, sugar, and oil are used as food preservatives.
1. Addition of salt: It is one of the oldest methods of preserving food. The addition of salt removes the moisture content in the food by the process of osmosis. This prevents the growth of bacteria and reduces the activity of microbial enzymes. Meat, fish, gooseberry, lemon, and raw mangoes are preserved by salting. Salt is also used as a preservative in pickles, canned foods, etc.

2. Addition of sugar: Sugar/Honey is added as a preservative to increase the shelf life of fruits and fruit products like jams, jellies, squash, etc. The hygroscopic nature of sugar/honey helps in reducing the water content of food and also minimizing the process of oxidation in fruits.

3. Addition of oil: The addition of oil in pickles prevents the contact of air with food. Hence microorganisms cannot grow and spoil the food.

Samacheer Kalvi 9th Science Guide Chapter 21 Nutrition and Health

B. Synthetic preservatives:
Synthetic food preservatives like sodium benzoate, citric acid, vinegar, sodium meta bisulphate, and potassium bisulphate are added to food products like sauces, jams, jellies, packed foods, and ready-to-eat foods. These preservatives delay microbial growth and keep the food safe for a long duration.

Samacheer Kalvi 9th Science Guide Chapter 16 Applied Chemistry

Tamilnadu State Board New Syllabus Samacheer Kalvi 9th Science Guide Pdf Chapter 16 Applied Chemistry Text Book Back Questions and Answers, Notes.

Samacheer Kalvi 9th Science Solutions Chapter 16 Applied Chemistry

9th Science Guide Applied Chemistry Text Book Back Questions and Answers

I. Choose the correct answer :

Question 1
One Nanometre is
(a) 107metre
(b) 10-8 metre
(c) 10-6 metre
(d) 10-9metre
Answer:
(d) 10-9 metre
Hint: 1 nanometre is also called one billionth of a metre

 Samacheer Kalvi 9th Science Guide Chapter 16 Applied Chemistry

Question 2.
The antibiotic Penicillin is obtained from……………….
(a) plant
(b) microorganism ,
(c) animal
(d) sunlight
Answer:
(b) microorganism

Question 3.
1% solution of Iodoform is used as
(a) antipyretic
(b) antimalarial
(c) antiseptic
(d) antacid
Answer:
(c) antiseptic

Question 4.
The cathode of an electrochemical reaction involves ………………….
(a) oxidation
(b) reduction
(c) neutralisation
(d) catenation
Answer:
(b) reduction
Hint : It involves gain of electrons

 Samacheer Kalvi 9th Science Guide Chapter 16 Applied Chemistry

Question 5.
The age of a dead animal can be determined by using an isotope of …………………
(a) carbon
(b) iodine
(c) phosphorous
(d) oxygen
Answer:
(a) carbon
Hint : C614 isotope is used

Question 6.
Which of the following does not contain natural dyes?
(a) Potato
(b) Beetroot.
(c) Carrot
(d) Turmeric
Answer:
(a) Potato

 Samacheer Kalvi 9th Science Guide Chapter 16 Applied Chemistry

Question 7.
This type of food protect us from deficiency diseases.
(a) Carbohydrates
(b) Vitamins
(c) Proteins
(d) Fats
Answer:
(b) vitamins

Question 8.
Radiochemistry deals with
(a) oxidants
(b) batteries
(c) isotopes
(d) nanoparticles
Answer:
(e) isotopes

 Samacheer Kalvi 9th Science Guide Chapter 16 Applied Chemistry

Question 9.
The groups responsible for the colour of an organic compound is called
(a) isotopes
(b) auxochrome
(e) chromogen
(d) chromophore
Answer:
(d) chromophore

Question 10.
Chlorinated hydrocarbons are used as
(a) fertilizers ,
(b) pesticides
(c) food colourants
(d) preservatives
Answer:
b) pesticides

 Samacheer Kalvi 9th Science Guide Chapter 16 Applied Chemistry

II. Fill In the blanks:

1. ………….. is an electrochemical cell which converts electrical energy into chemical change
(Reaction).
Answer:
Electrolytic cell

2. Painkiller drugs are called ………………..
Answer:
Analgesics

3. Indigo is a …………… dye.
Answer:
Vat

4. ……………and……………..are macronutrients required for plant growth.
Answer:
Nitrogen, Phosphorous, and Potassium

 Samacheer Kalvi 9th Science Guide Chapter 16 Applied Chemistry

5. _____ is a chemical used in fingerprint analysis.
Answer:
Ninhydrin

III. Match the following:

Question1.

Column I Column II
Antipyretics Large surface area
Corrosion  prevention Iodine – 131
Hyperthyroidism Fever
Nanoparticle Bodybuilding
Proteins Electroplating

Answer:

Column I Column II
Antipyretics Fever
Corrosion  prevention Electroplating
Hyperthyroidism Iodine – 131
Nanoparticle Large surface area
Proteins Bodybuilding

IV. Answer briefly :

Question 1.
What is Radio Carbon Dating?
Answer:
Radiocarbon dating is a method by which the age of fossil wood or animal is determined using the C-14 isotope.

Question 2.
What are called Anaesthetics? How are they classified?
Answer:
The drugs which cause loss of sensation are called Anaesthetics.
Types of Anaesthetics

General anesthetics: They are the agents, which bring about loss of all modalities of sensation, particularly pain along with ‘reversible’ loss of consciousness.
Local anesthetics: They prevent the pain sensation in localised areas without affecting the degree of consciousness.

 Samacheer Kalvi 9th Science Guide Chapter 16 Applied Chemistry

Question 3.
What is the need for chemical fertilizers in crop fields?
Answer:
The need for chemical fertilizers In crop fields is to supply essential micro and macronutrients required for crop growth.

Question 4.
What is Forensic chemistry related to?
Answer:
Forensic chemistry applies scientific principles, techniques, and methods to the investigation of crime.

 Samacheer Kalvi 9th Science Guide Chapter 16 Applied Chemistry

V. Answer in detail :

Question 1.
Explain the types of dyes based on their method of application.
Answer:
Dyes are classified in two ways, one, based on the method of application and others on their parent structure.
Based on the method of application:

  • Acid dyes: These are acidic in nature and used for dyeing animal fibres and synthetic fibres. These can be used for protein fibre such as wool and silk. E.g. Picric acid, Naphthol yellow-s
  • Basic dyes: These are basic dyes containing basic group (- NH2,- NHR, – NR2). They are used for dyeing animal fibres and plant fibres.
  • Mordant dyes or Indirect dyes: These dyes have a poor affinity for cotton fabrics and hence do not dye directly. They require pretreatment of the fibre with a mordant. Mordant (latin: mordere = to bite) is a substance which can be fixed to the fibre and then can be combined with the dye to form an insoluble complex called lake. Aluminium, chromium, and iron salts are widely used as mordants. E.g. alizarin.
  • Direct dyes: They have high affinity for cotton, rayon and other cellulose fibre. So they are applied directly as they fix firmly on the fabric. E.g. Congo red
  • Vat dyes: It can be used only on cotton and, not on silk and wool. This dyeing is a continuous process and is carried out in a large vessel called vat. So it is called as vat dye. E.g. Indigo

Question 2.
Name various food additives and explain their functions.
Answer:
Samacheer Kalvi 9th Science Guide Chapter 16 Applied Chemistry 1

VI. Higher Order Thinking Skills :

Question 1.
Batteries that are used in mobile phone can be recharged. Likewise, can you recharge the batteries used in watches? justify your answer.
Answer:
The type of batteries used in watches is Primary cell. (Mercury-Oxide battery)
The type of batteries are used in mobile phone is Secondary cell. (Lithium -ion polymer battery)
The differences between primary and secondary cell are as follow:

Primary Cell Secondary cell
1. The chemical reaction of primary cell is irreversible. The chemical reaction is reversible.
2. Hence it can not be recharged. Hence it can be recharged.

Question 2.
Sudha met with a fire accident. What kind of drug(s), she must take?
Answer:
Analgesics are to be administered to reduce the pain followed by antibiotics to prevent infection by microbes.

 Samacheer Kalvi 9th Science Guide Chapter 16 Applied Chemistry

Question 3.
The soil pH of cropland is 5. What kind of fertilizers should be used in that land?
Answer:

  • pH of 5 indicates the soil is Acidic.
  • So alkaline fertilizers should be used.
    (e.g.,) Potash fertilizers, Nitrogen fertilizers.

Intext Activities

ACTIVITY – 1

With the help of your teacher, construct the galvanic cell using lemon and potato. Identify their anode, cathode and electrolyte.
Aim: To construct a galvanic cell using lemon (or) potato
Materials required :

  1. A large fresh juicy lemon,
  2. Zinc coated nail,
  3. Small copper coin,
  4. LED light,
  5. Connecting wires

Procedure :

  1. Insert the copper coin into the lemon.
  2. Push a zinc-coated nail into the other side of the lemon.
  3. The copper coin and zinc-coated nail are connected to a low voltage LED bulb.
  4. Now observe the results, (happenings).

Observation:

  1. Copper coin acts as the cathode, zinc-coated nail acts as Anode. Lemon juice acts as an electrolyte.
  2. We observe glow of LED light, which confirms the electricity to flow through the lemon.

Conclusion: Galvanic cell usifi^lpmon is constructed.

 Samacheer Kalvi 9th Science Guide Chapter 16 Applied Chemistry

9th Science Guide Applied Chemistry Additional Important Questions and Answers

I. Choose the correct answer :

Question 1.
Nanoparticles are unstable when they come in contact with ………………..
(a) air
(b) Hydrogen
(c) Oxygen
(d) all the above
Answer:
(c) Oxygen

Question 2.
Which is the incorrect statement in the following?
(a) The structure of nano material is in between an atom and bulk material.
(b) Nanomaterials exist in the corresponding bulk materials.
(c) Nanomaterials have the extremely large surface area to volume ratio.
(d) SEM is used analyse the surface properties of a nanoparticle with high resolution.
Answer:
(b) Nanomaterials exist in the corresponding bulk materials

 Samacheer Kalvi 9th Science Guide Chapter 16 Applied Chemistry

Question 3.
Which anesthetic forms a toxic carbonyl chloride?
(a) Nitrous oxide
(b) Ether
(c) Chloroform
(d) Iodoform
Answer:
(c) Chloroform

Question 4.
Paracetamol is a …………….
(a) Analgesic
(b) Antiseptic
(c) Antimalarial
(d) Antipyretic
Answer:
(c) Antipyretic

Question 5.
The antiseptic used for cleansing the wounds is ………………..
(a) Phenol
(b) Iodoform
(C) Ether
(d) Hydrogen peroxide
Answer:
(d) Hydrogen peroxide

 Samacheer Kalvi 9th Science Guide Chapter 16 Applied Chemistry

Question 6.
Antimalarial drug obtained from Cinchona bark is ……………………
(a) Quinine
(b) Morphine.
(e) Primaquine
(d) Pyrimethamine
Answer:
(a) Quinine

Question 7.
The drug that ¡s known as “Miracle drug” is ………………….
(a) Chloroquinine
(b) Penicillin
(C) Aspirin. .
(d) Paràcetamol
Answer:
(b) Penicillin

 Samacheer Kalvi 9th Science Guide Chapter 16 Applied Chemistry

Question 8.
In Daniel cell, saturated solution of potassium chloride (KCl) acts as ……………..
(a) Anode
(b) Cathode
(c) Salt bridge
(d) Electrolyte
Answer:
(c) Salt bridge

Question 9.
The process of purifying metals by electrolysis ¡s known as ……………..
(a) Electroplating
(b) Electrorefining
(e) Electromanufacturing
(d) None of these
Answer:
(b) Electrorefining

Question 10.
Which one among the following statements is correct?
(a) Galvanic cell converts electrical energy into chemical energy.
(b) Reduction takes place at the anode.
(c) Oxidation reaction takes place at the cathode.
(d) None of these
Answer:
(d) None of these

 Samacheer Kalvi 9th Science Guide Chapter 16 Applied Chemistry

Question 11.
Isotopes are atoms with different number of ………………………
(a) protons
(b) neutrons
(c) electrons
(d) None of these
Answer:
(b) neutrons

Question 12.
The radioisotope used for location of blood clot and circulation disorders is …………………..
(a) Na – 24
(b) I – 131
(c) Fe – 59
(d) Co – 60
Answer:
(a) Na – 24

 Samacheer Kalvi 9th Science Guide Chapter 16 Applied Chemistry

Question 13.
The dye that can only be used on cotton is …………………….
(a) Mordant dye
(b) Vat dye
(c) Direct dye
(d) Basic dye
Answer:
(b) Vat dye

Question 14.
Which one of the following is a flavour enhancer?
(a) Sodium nitrite
(b) Sodium benzoate
(c) Cyclamate
(d) Monosodium Glutamate
Answer:
(d) Monosodium Glutamate

Question 15.
The compound that gets redUced ¡n the alcohol test is ……………………
(a) Silver nitrate
(b) Sulphuric acid
(C) Water
(d) Potassium dichromate
Answer:
(d) Potassium dichromate

 Samacheer Kalvi 9th Science Guide Chapter 16 Applied Chemistry

II. Fill in the blanks:

1. Nanotechnology deals with materials which are smaller than …………………..
Answer:
100 nanometres

2. The metallic nanoparticles can be used as ………………….
Answer:
Very active catalysts

3. Nanoparticle substances are incorporated in fabrics to prevent …………………..
Answer:
the growth of bacteria

 Samacheer Kalvi 9th Science Guide Chapter 16 Applied Chemistry

4. The word “drug” is derived from the French word “droque” which means a ………………..
Answer:
dry herb

5. …………… is the safest of the anesthetic drugs.
Answer:
Nitrus oxide

6. The Analgesics are also called as …………………
Answer:
Pain killer (or) Pain relievers

 Samacheer Kalvi 9th Science Guide Chapter 16 Applied Chemistry

7. ………………. produce sleep and unconsciousness.
Answer:
Narcotics

8. Antiseptics are used internally to treat infections of the …………… and ……………..
Answer:
Intestine, Bladder

9. Malaria is a ……………… borne disease.
Answer:
vector

10. ………………. is used as an additive with other antimalarial drugs.
Answer:
Chloroquine

 Samacheer Kalvi 9th Science Guide Chapter 16 Applied Chemistry

11. ……………. is extensively used for rheumatic fever, narrowing of the heart wall, bronchitis, and pneumonia.
Answer:
Penicillin

12. …………… is due to an imbalance in the acidity in the stomach.
Answer:
Burning sensation

13. The solution having ions is called ………………..
Answer:
Electrolyte

14. …………….. is the loss of electrons.
Answer:
Oxidation

 Samacheer Kalvi 9th Science Guide Chapter 16 Applied Chemistry

15. The process of depositing a thin layer of one metal over another metal by the process of electrolysis is called …………………….
Answer:
Electroplating

16. When metals of a very high degree of purity are required,………………… is done.
Answer:
Electrorefining

17. The isotope used in Radiocarbon dating is …………………..
Answer:
C-14

 Samacheer Kalvi 9th Science Guide Chapter 16 Applied Chemistry

18. The chromophore and auxochrome theory was proposed by ……………………
Answer:
Otto Witt

19. ……………… is one of the main criteria to be considered for the selection of crop (or) remediation of soil.
Answer:
Soil pH

20. Vitamin C is also powerful ……………….. that prevents food from oxidising.
Answer:
Antioxidant

21. ……………. is one of the most important evidence in crime investigation.
Answer:
Fingerprint

 Samacheer Kalvi 9th Science Guide Chapter 16 Applied Chemistry

III. Match the following:

Question 1.

Name of the Drug Purpose Example
1. Antipyretics Kills the microorganism Chloroform
2. Anaesthetics Pain reliever Novalgin
3. Antiseptics Reduction of fever paracetamol
4. Analgesics Cure for malaria Quinine
5. Antimalarial Loss of sensation Hydrogen peroxide

Answer:

Name of the Drug purpose Example
1. Antipyretics Reduction of fever paracetamol
2. Anaesthetics Loss of sensation Chloroform
3. Antiseptics Kills the microorganism Hydrogen peroxide
4. Analgesics Pain reliever Novalgin
5. Antimalarial Cure for malaria Quinine

Question 2.

Column I Column II
Cathodic electrolyte Potassium chlorate (KClO3)
Anodic electrolyte Potassium chloride (KCl)
Salt bridge sulphate CuSO4
Electro manufacturing Zinc sulphate(ZnSO4)

Answer:

Column I Column II
Cathodic electrolyte Copper sulphate CuSO4
Anodic electrolyte Zinc sulphate(ZnSO4)
Salt bridge Potassium chloride (KCl)
Electro manufacturing Potassium chlorate (KClO3)

 Samacheer Kalvi 9th Science Guide Chapter 16 Applied Chemistry

Question 3.

Column I Column II
Phosphorous-30 Cancer
Iodine-131 Pregnancy disorder
Cobalt-60 Hyperthyroidism
Iron-59 Blood disorder
Sodium-24 Circulation disorder

Answer:

Column I Column II
Phosphorous-30 Blood disorder
Iodine-131 Hyperthyroidism
Cobalt-60 Cancer
Iron-59 Pregnancy disorder
Sodium-24 Circulation disorder

Question 4.

Column I Column II
Indirect dyes Congo red
Direct dyes Alizarin
Vat dyes Methylene blue
Basic dyes Picric acid
Acid dyes Indigo

Answer:

Column I Column II
Indirect dyes Alizarin
Direct dyes Congo red
Vat dyes Indigo
Basic dyes Methylene blue
Acid dyes Picric acid

 Samacheer Kalvi 9th Science Guide Chapter 16 Applied Chemistry

IV. State whether true or false. If false, correct the statement:

1. Nanoparticles are easy to synthesis, isolate, and apply.
Answer:
False,
Correct statement: Nanoparticles are difficult to synthesis, isolate, and apply.

2. When cancer occurs, cells are reproduced in a controlled manner.
Answer:
False.
Correct statement: When cancer occurs, cells are reproduced in an uncontrolled manner.

3. General anaesthetics cause pain along with ‘reversible’ loss of consciousness
Answer:
False.
Correct statement: General anaesthetics relieve pain along with reversible loss of consciousness.

 Samacheer Kalvi 9th Science Guide Chapter 16 Applied Chemistry

4. Malaria decreases body temperature.
Answer:
False.
Correct statement: Malaria increases the body temperature

5. High concentration of antibiotics is needed for Effective action.
Answer:
False. .
Correct statement: Low concentration of antibiotics is needed for effective action.

6. Antacids provide relief from burning sensation in the stomach.
Answer:
True,

 Samacheer Kalvi 9th Science Guide Chapter 16 Applied Chemistry

7. In Daniel’s cell, Zinc metal acts as the cathode, and Copper metal acts as Anode.
Answer:
False.
Correct statement: In Daniel’s cell, Zinc metal acts as Anode, and Copper metal acts as Cathode.

8. Radioisotopes can be easily detected and estimated quantitatively.
Answer:
True.

9. Dyes are aromatic compounds originated from plants and insects.
Answer:
True.

 Samacheer Kalvi 9th Science Guide Chapter 16 Applied Chemistry

10. Dye should be fast to light.
Answer:
True.

11. Vinegar is used as an antioxidant.
Answer:
False.
Correct statement: Vinegar is used as a preservative.

12. Reduction of alcohol results in oxidation of dichromate to chromic ion.
Answer:
False.
Correct statement: Oxidation of alcohol results in a reduction of dichromate to chromic ion

 Samacheer Kalvi 9th Science Guide Chapter 16 Applied Chemistry

V. Assertion and Reason type:

Mark the correct choice as:
(a) If both assertion and reason are true and Reason is the correct explanation of Assertion.
(b) If both assertion and reason are true but reason is not the correct explanation of assertion.
(c) If assertion is true but reason is false.
(d) If assertion is false but reason is true.

Question 1.
Assertion (A) : Nanoparticles interact with impurities.
Reason (R) : Nanoparticles are less reactive.
Answer:
(c) Assertion is true but the reason is false
Reason (R) : Nanoparticles are highly reactive.

Question 2.
Assertion (A) : Antiseptic is a substance that prevents infections caused by disease-causing pathogens.
Reason (R) : Antiseptics either kill the microorganism or prevent their growth.
Answer:
(a) Both assertion and reason are true and Reason is the correct explanation of Assertion

 Samacheer Kalvi 9th Science Guide Chapter 16 Applied Chemistry

Question 3.
Assertion (A) : After eating fruits (or) vegetables, one may feel uncomfortable due to a burning sensation.
Reason (R) : Burning sensation is due to an imbalance in the acidity of the stomach.
Answer:
(d) Assertion is false but the reason is true
Assertion (A) : After eating oily and spicy foods, one may feel uncomfortable due to a burning sensation.

Question 4.
Assertion (A) : Metals like iron are electroplated with chromium.
Reason (R) : Electroplating is done to protect chromium from rusting.
Answer:
(c) Assertion is true but reason is false
Reason (R) : Electroplating is done to protect iron from rusting.

Question 5.
Assertion (A) : It is possible to detect alcohol drunken drivers.
Detection is done through the electrochemical redox reaction of alcohol.
Answer:
(a) Both assertion and reason are true and Reason is the correct explanation of Assertion

 Samacheer Kalvi 9th Science Guide Chapter 16 Applied Chemistry

Question 6.
Assertion (A) : Our retinal print can be forged.
Reason (R) : Our retinal print is unique.
Answer:
(d) Assertion is false but reason is true
Assertion ( A) : Our retinal print cannot be forged.

VI. Very short answer type :

Question 1.
What are the specific qualities of nanoparticles?
Answer:

  • Larger surface area
  • High surface energy.
  • Spatial confinement
  • Reduced imperfections.

Question 2.
List out the instruments used to analyse nanoparticles.
Answer:

  • Scanning Electron Microscope (SEM)
  • Tunneling Electron Microscope (TEM).
  • Atomic Force Microscope (AFM).

 Samacheer Kalvi 9th Science Guide Chapter 16 Applied Chemistry

Question 3.
What is antipyretics?
Answer:
Antipyretics are the compounds used to reduce fever, (i.e.) lowering the body temperature to normal.

Question 4.
How are antiseptics used?
Answer:
External use: To cleanse wounds.
Internal use: To treat infections of the intestine and bladder.

Question 5.
Mention the uses of Penicillin.
Answer:
Penicillin is used for

  • Rheumatic fever,
  • Narrowing of the heart wall.
  • Bronchitis,
  • Pneumonia.

 Samacheer Kalvi 9th Science Guide Chapter 16 Applied Chemistry

Question 6.
What are the main sources of Antibiotics?
Answer:
Main sources of Antibiotics are

  • Bacteria
  • Fungi and
  • Actinomycetes.

Question 7.
Name any five natural antibiotics.
Answer:

  • Honey
  • Garlic
  • Ginger
  • Neem
  • Turmeric.

Question 8.
What is an Electrochemical cell?
Answer:
A device that makes use of a chemical change to produce electricity (or) electricity to produce chemical change is called an Electrochemical cell.

 Samacheer Kalvi 9th Science Guide Chapter 16 Applied Chemistry

Question 9.
What is a Daniel cell?
Answer:
Daniel cell is a type of galvanic cell in which zinc metal acts as anode and copper metal as cathode.

Question 10.
What is radioactive decay?
Answer:

  • The unstable isotopes of elements lose their energy in the form of radiation to become stable.
  • This phenomenon is called radioactive decay.

Question 11.
What is Vermicompost?
Answer:
Vermicompost is one of the natural fertilizers produced from domestic wastes.

 Samacheer Kalvi 9th Science Guide Chapter 16 Applied Chemistry

Question 12.
What is a balanced diet?
Answer:
A diet that contains all the three foods such as (i) Bodybuilding foods, (ii) Energy giving foods, and (iii) Protective foods in the right proportion are called a Balanced diet.

Question 13.
Mention the use of a Biometric system.
Answer:
The biometric system compares the body prints to the specimen data stored in the system to verify the identity of a person.

VII. Answer briefly :

Question 1.
What is called as Applied Chemistry?
Answer:
Application of chemical principles and theories to various fields in order to achieve specific results or to solve real-world problems is called applied chemistry.

 Samacheer Kalvi 9th Science Guide Chapter 16 Applied Chemistry

Question 2.
Write short notes on nanochemistry.
Answer:

  • Nanochemistry is a branch of nanoscience, that deals with the chemical applications of nanomaterials in nanotechnology.
  • It involves the synthesis and manipulation of materials at the atomic and molecular level.

Question 3.
Mention medical applications of Nanorobotics.
Answer:

  • Nanorobotics is used in medicine and space technology.
  • It plays important role in Bio-medicine in the treatment of cancer.

Question 4.
Define Drug.
Answer:
According to the World Health Organisation (WHO),
Drug is a substance or product that is used or intended to be used to modify or explore physiological systems or pathological states for the benefits of the recipient.

 Samacheer Kalvi 9th Science Guide Chapter 16 Applied Chemistry

Question 5.
What is an Analgesics? How is it useful?
Answer:

  • Analgesics are compounds which relieve all sorts of pains without the loss of consciousness.
  • It is useful to treat
    (a) Headaches
    (b) Myalgia and
    (c) arthralgia.

Question 6.
What is known is Antibiotics?
Answer:
Many microorganisms (bacteria, fungi, and molds) produce certain chemicals which inhibit the growth (or) metabolism of some other disease-causing microorganism. Such chemical compounds are known as Antibiotics.

Question 7.
Write brief notes on processes involved in cell reactions.
Answer:
An electrochemical cell involves two reactions simultaneously.

  • Oxidation : Oxidation is the loss of electrons, that takes place at the anode.
    Metal → Metal ion + electron(s)
  • Reduction: Reduction is the gain of electrons, that takes place at the cathode.
    Metal ion + electron(s) → Metal.

 Samacheer Kalvi 9th Science Guide Chapter 16 Applied Chemistry

Question 8.
How does a galvanic cell produce electricity?
Answer:

  • At the anode, oxidation takes place which releases electrons.
  • These electrons are attracted by the cathode.
  • Thus electrons flowing from anode to cathode produce electricity.

Question 9.
Mention the applications of electroplating with an example.
Answer:
Applications of Electroplating :

  • Electroplating is done to protect the metal from corrosion, (e.g) chrome -plating.
  • Electroplating is done to beautify the surface of a metal, (e.g) Gold plating.
  • Broken parts of machinery require electrodeposition of metal between broken parts.

Question 10.
List out the characteristics of Dye.
Answer:
Characteristics of Dye:

  • Dye should have a suitable colour.
  • Dye should be able to fix itself.
  • Dye should be fast to light,
  • Dye should be resistant to the action of water, dilute acids, and alkalies.

 Samacheer Kalvi 9th Science Guide Chapter 16 Applied Chemistry

Question 11.
Define Pesticides.
Answer:
According to the World Health Organisation (WHO),
Pesticides are chemical compounds that are used to kill pests including insects, rodents, fungi, and unwanted plants (weeds).

Question 12.
How can Fingerprints be identified?
Answer:

  • Fingerprints on smooth surfaces can be identified by the application of light or dark powder.
  • Occult (hidden) Fingerprints are made visible by the use of Ninhydrin, which turns purple.
  • Fingerprints can be made visible by high powered laser light.

Question 13.
How is alcohol consumption detected?
Answer:

  • The person being tested blows through a tube, which bubbles the breath through a solution containing Sulphuric acid, Potassium dichromate, water and silver nitrate.
  • Oxidation of alcohol results in the reduction of dichromate to chromatic ions with a change in color from orange to green.

 Samacheer Kalvi 9th Science Guide Chapter 16 Applied Chemistry

Question 14.
What is Chemotherapy?
Answer:
Treatment of certain diseases by destroying the invading organism without damaging the cells of the host, by the use of certain organic compounds is known as chemotherapy. It is widely used for treating cancer.

VIII. Answer in detail :

Question 1.
Draw the cell diagram of Daniel cell. Give its reactions.
Answer:
Samacheer Kalvi 9th Science Guide Chapter 16 Applied Chemistry 2

Question 2.
Daniel cell
Answer:
Samacheer Kalvi 9th Science Guide Chapter 16 Applied Chemistry 3

Question 3.
List the applications of Nanochemistry.
Answer:
Applications of Nanochemistry :

  • The metallic nanoparticles can be used as very active catalysts.
  • Chemical sensors form nanoparticles and nanowires enhance the sensitivity and sensor selectivity.
  • Nanocoatings and nanocomposites are found useful in making a variety of products such as sports equipment, bicycles, and automobiles etc.
  • Nanotechnology is being applied in the die production of synthetic skin and implant surgery.
  • Nanomaterials that conduct electricity are being used in electronics as minute conductors to produce circuits for microchips.
  • Nanomaterials are used in the preparation of cosmetics, deodorants, and sunscreen lotion. They are used to improve moisturizers, without making them too oily.
  • Nanoparticle substances are incorporated in fabrics to prevent the growth of bacteria.

 Samacheer Kalvi 9th Science Guide Chapter 16 Applied Chemistry

Question 4.
Mention the drawbacks of Nanomaterials in chemistry.
Answer:
Drawbacks of nanomaterials in chemistry :

  • Nanoparticles are unstable when reacting with oxygen.
  • Their exothermic combustion with oxygen can easily cause an explosion.
  • Because nanoparticles are highly reactive, they inherently interact with impurities as well.
  • Nanomaterials are usually considered biologically harmful and toxic.
  • It is difficult to synthesis, isolate and apply them.
  • There are no hard-and-fast safe disposal policies for nanomaterials.

Question 5.
Account the role of Radioactive isotopes in Diagnosis and treatment in the Medical field?
Answer:
Radioisotopes are very useful to diagnose and treat many diseases. . Some of them are given below:

Samacheer Kalvi 9th Science Guide Chapter 16 Applied Chemistry 4

Samacheer Kalvi 9th Science Guide Chapter 16 Applied Chemistry 5

Question 6.
Give a comparative account of various drugs with their application and examples.
Answer:
Samacheer Kalvi 9th Science Guide Chapter 16 Applied Chemistry 6

Samacheer Kalvi 9th Science Guide Chapter 16 Applied Chemistry 7

 Samacheer Kalvi 9th Science Guide Chapter 16 Applied Chemistry

Question 7.
What are the applications of electrochemistry?
Answer:
Applications of electrochemistry :

  • It has been used to discover important technical processes for the production and purification of non-ferrous metals, and for the electro- synthesis of organic compounds.
  • Electrochemistry has been used to predict whether a particular reaction will occur or not.
  • The detection of alcohol in drunken drivers is possible through the electrochemical redox reaction of ethanol.
  • Production of metals like aluminum and titanium from their ores involves electrochemical reactions.
  • Diabetes blood sugar meters measure the amount of glucose in the blood through its redox potential.
  • Lead-acid batteries, lithium-ion batteries, and fuel cells are based on electrochemical cells.
  • A fuel cell is used to bring about the direct conversion of chemical energy into electrical energy.

Question 8.
Explain very briefly about various fields of Applied Chemistry.
Answer:
Various Fields of Applied Chemistry:

  • Nanochemistry: It is a branch of nanoscience that deals with the chemical applications of nanomaterials in nanotechnology.
  • Nanometre = 1/1,000,000,000 metre.
  • Pharmaceutical chemistry: It deals with the preparation of drugs and the study of the chemical composition, nature, behaviour, structure, and influence of the drug in an organism.
  • Electrochemistry: It deals with the relation between electrical energy and chemical change.
  • Radiochemistry: It is the study of the chemistry of radioactive and non-radioactive isotopes.
  • Dye chemistry: It is the study of dyes.
  • Agricultural chemistry: It deals application of chemical and biochemical knowledge to agricultural production, the processing of raw products into foods and beverages, and environmental monitoring and remediation.
  • Food chemistry: It involves the analysis, processing, packaging, and utilization of materials.
  • Forensic chemistry: It applies scientific principles, techniques, and methods to the investigation of crime.

Samacheer Kalvi 9th Science Guide Chapter 22 World of Microbes

Tamilnadu State Board New Syllabus Samacheer Kalvi 9th Science Guide Pdf Chapter 22 World of Microbes Text Book Back Questions and Answers, Notes.

Tamilnadu Samacheer Kalvi 9th Science Solutions Chapter 22 World of Microbes

9th Science Guide World of Microbes Text Book Back Questions and Answers

Samacheer Kalvi 9th Science Guide Chapter 22 World of Microbes

I. Choose the correct answer :

Question 1.
Which of the following is transmitted through air?
(a) Tuberculosis
(b) Meningitis
(c) Typhoid
(d) Cholera
Answer:
(a) Tuberculosis

Question 2.
One of the means of indirect transmission of a disease is
(a) sneezing
(b) coughing
(c) vectors
(d) droplet infection
Answer:
(c) vectors

Samacheer Kalvi 9th Science Guide Chapter 22 World of Microbes

Question 3.
Diptheria affects the
(a) lungs
(b) throat
(c) blood
(d) liver
Answer:
(b) Throat

Question 4.
The primary organ infected during tuberculosis is
(a) bone marrow
(b) intestine
(c) spleen
(d) lungs
Answer:
(d) lungs

Samacheer Kalvi 9th Science Guide Chapter 22 World of Microbes

Question 5.
Microbes that generally enter the body through nose are likely to affect
(a) gut
(b) lungs
(c) liver
(d) lymph nodes
Answer:
(b) lungs

Question 6.
The organ affected by jaundice is
(a) liver
(b) lungs
(c) kidney
(d) brain
Answer:
(a) liver

Samacheer Kalvi 9th Science Guide Chapter 22 World of Microbes

Question 7.
Poliomyelitis virus enters the body through
(a) skin
(b) mouth and nose
(c) ears
(d) eye
Answer:
(b) mouth and nose

II. Fill in the blanks:

1. …………….. break down organic matter and animal waste into ammonia.
Answer:
Decomposers

2. Typhoid fever is caused by ………………
Answer:
salmonella typhi

Samacheer Kalvi 9th Science Guide Chapter 22 World of Microbes

3. H1N1 virus causes……………..
Answer:
swine flu

4. …………….. is a vector of viral disease dengue.
Answer:
Aedes aegypti mosquito

5. …………….. vaccine gives considerable protection against tuberculosis.
Answer:
BCG

Samacheer Kalvi 9th Science Guide Chapter 22 World of Microbes

6. Cholera is caused by…………….. and malaria is caused by………………
Answer:
bacteria (Vibrio cholera), protozoa (plasmodium)

III. Expand the following:

  1. ORS – Oral Rehydration Solution.
  2. HIV – Human Immunodeficiency Virus.
  3. DPT – Diphtheria Pertussis Tetanus.
  4. WHO – World Health Organisation.
  5. BCG – Bacillus Calmette Guerin.

IV. Pick out the odd one :

  1. AIDS, Retrovirus, Lymphocytes, BCG, – BCG.
  2. A bacterial disease, Rabies, Cholera, Common cold, and Influenza – Cholera.

V. State whether True or False. If false, correct the statement:

1. Rhizobium, associated with root nodules of leguminous plants fixes atmospheric nitrogen.
Answer:
True.

Samacheer Kalvi 9th Science Guide Chapter 22 World of Microbes

2. Non-infectious diseases remain confined to the person who develops the disease and do not spread to others.
Answer:
True.

3. The process of vaccination was developed by Jenner.
Answer:
True.

4. Hepatitis B is more dangerous than Hepatitis A.
Answer:
True.

Samacheer Kalvi 9th Science Guide Chapter 22 World of Microbes

VI. Match the following :

Swine flu Human Papilloma vims Influeuza vims HINl
Genital warts Human Immunodeficiency Vims
AIDS Mycobacterium
Tuberculosis Influenza vims HINl

Answer:

Swine flu Influenza vims HINl
Genital warts Human Papilloma vims
AIDS Human Immunodeficiency Vims
Tuberculosis Mycobacterium

VII. Define the following:

1. Pathogen
2. Bacteriophages
3. Vaccines
4. Prions
Answer:
1. Pathogen – A pathogen is a biological agent that causes disease due to its host E.g. Bacteria, Virus, etc.,
2. Bacteriophages – Virus that infect bacterial cells E.g. T4 bacteriophage.
3. Vaccines – Preparation of antigenic proteins of pathogens (weakened or killed) which on inoculation into a healthy person provides temporary / permanent immunity against a particular disease.
4. Prions – Prions are viral particles which contain only proteins. They do not contain nucleic acid.

Samacheer Kalvi 9th Science Guide Chapter 22 World of Microbes

VIII. Answer very briefly :

Question 1.
Distinguish between Virion and Viroid.
Answer:
Virion

  1. Simple vims particle.
  2. Grow and multiply in living cells.

Viriod

  1. The protein-free pathogenic RNA of vims.
  2. Found in plant cells and causes disease in plants.

Question 2.
Name the vector of the malarial parasite. Mention the species of malarial parasite which cause malignant and fatal malaria.
Answer:
The vector of the malarial parasite is the female Anopheles mosquito.
Malaria caused by Plasmodium falciparum is malignant and fatal.

Samacheer Kalvi 9th Science Guide Chapter 22 World of Microbes

Question 3.
What is triple antigen? Mention the disease which can be prevented by using the antigen.
Answer:
Triple antigen : It is combination of three vaccines (DPT).
Preventable diseases : Diptheria, Pertussis (Whooping cough) and Tetanus.

Question 4.
Name the chronic diseases associated with respiratory system.
Answer:
Chronic diseases associated with the respiratory system are; Diptheria, Whooping Cough, Tuberculosis.

Question 5.
Name the organism causing diarrhoeal disease and give one precaution against it.
Answer:

  1. Rotavirus.
  2. Precaution : Proper sanitation and hygiene.

Samacheer Kalvi 9th Science Guide Chapter 22 World of Microbes

Question 6.
Name two common mosquitoes and the diseases they transmit.
Answer:
Anopheles mosquito and Aedes aegypti mosquito are common mosquitoes that transmit malaria, Chikungunya and Dengue.

IX. Answer briefly :

Question 1.
Give an account of classification, of bacteria based on the shape.
Answer:
Bacteria are microscopic, single-celled prokaryotic organisms without a nucleus and other cell organelles. Although the majority of bacterial species exist as single-celled forms, some appear to be filaments of loosely joined cells. The size varies from less than 1 to 10 µm in length and 0.2 to 1 µm micrometer in width.
Based on the shapes, bacteria are grouped as:

  1. Spherical shaped bacteria called cocci (or coccus for a single cell).
  2. Rod-shaped bacteria called bacilli (or bacillus for a single cell).
  3. Spiral shaped bacteria called spirilla (or spirillum for single cell)

Question 2.
Describe the role of microbes in agriculture and industries.
Answer:
Microbes in Agriculture :
Microbes play an important role in agricultrue as biocontrol agents and biofertilizers.
(i) Biocontrol agents :
Microorganisms used for controlling harmful or pathogenic organisms and pests of plants are called as biocontrol agents Biopesticides.
(E.g) Bacillus Thuringiensis.(Bt) is a species of bacteria that produces a protein called as ‘cry’ protein.

(ii) Biofertilizers:

  • Microorganisms which enrich the soil with nutrients are called as biofertilizers.
  • Bacteria, cyanobacteria and fungi are the main sources of biofertilizers .
  • Atomspheric nitrogen has to be converted to available form of nitrogen.
    Example: Azotobacter, Nostoc (free living), Symbiotic microbes like Rhizobium, Frankia.

Microbes in Industries
Microorganisms play an important role in the production of wide variety of valuable products for the welfare of human beings.

Production of fermented beverages: Beverages like wine are produced by fermentation of grape fruits by Saccharomyces cerevisiae.

Curing of coffee beans, tea leaves and tobacco leaves : Beans of coffee and cocoa, leaves of tea and tobacco are fermented by the bacteria Bacillus megaterium. This gives the special aroma.

Production of curd : Lactobacillus sp. converts milk to curd.

Production of organic acids, enzymes and vitamins : Oxalic acid, acetic acid and citric acid are produced by fungus Aspergillus niger. Enzymes like lipases, invertase, proteases, and glucose oxidase are derived from microbes. Yeasts are rich source of vitamin-B complex.

Samacheer Kalvi 9th Science Guide Chapter 22 World of Microbes

Question 3.
Explain the various types of viruses with examples.
Answer:
Viruses are categorised as :
1. Plant virus : Virus that infect plants.
E.g. Tobacco mosaic vims, Potato vims, Cauliflower mosaic virus.
Samacheer Kalvi 9th Science Guide Chapter 22 World of Microbes 1

2. Animal virus : Vims that infect animals.
E.g. Adenovims, Retrovims (HIV), Influenza vims, Polio vims.
Samacheer Kalvi 9th Science Guide Chapter 22 World of Microbes 2

3. Bacteriophages : Vims that infect bacterial cells.
E.g.T4 bacteriophage.
Samacheer Kalvi 9th Science Guide Chapter 22 World of Microbes 3

Samacheer Kalvi 9th Science Guide Chapter 22 World of Microbes

Question 4.
Suggest the immunization schedule for a new born baby till 12 months of age. Why it is necessary to follow the schedule?
Answer:
The immunization schedule must be followed so that the vaccines administered will protect the children in the future from infectious and life-threatening diseases.

Immunization Schedule for Children
Samacheer Kalvi 9th Science Guide Chapter 22 World of Microbes 4

X. Assertion and Reason :

Mark the correct statement as:
(a) If both A and R are true and R is correct explanation of A.
(b) If both A and R are true but R is not the correct explanation of A.
(c) If A is true but R is false.
(d) If both A and R are false.

Question 1.
Assertion : Chicken pox is a disease indicated by scars and marks in the body.
Reason : Chicken pox cenlses rashes on face and further spreads throughout the body.
Answer:
(a) Both A and R are true and R is correct explanation of A

Samacheer Kalvi 9th Science Guide Chapter 22 World of Microbes

Question 2.
Assertion: Dengue can be treated by intake of antibiotics.
Reason : Antibiotics blocks the multiplication of viruses.
Answer:
(d) Both A and R are false

XI. Higher Order Thinking Skills :

Question 1.
Suggest precautionary measures you can take in your school to reduce the incidence of infectious disease.
Answer:

  • Clean and hygienic environment should be maintained inside and outside the school.
  • Enough first aid medicines should be kept in the school.
  • Proper awareness about healthy diet and health instructions should be instructed to the students.
  • If a student is identified with disease, it must be properly communicated to the students and nearby health authorities.
  • The infected student / person must be kept away from other students in order to avoid the spread of infection.

Question 2.
Tejas suffered from typhoid while, Sachin suffered from tuberculosis. Which disease could have caused more damage and why?
Answer:
Tuberculosis is more dangerous than typhoid.
Reason : Tuberculosis (TB) primarily affects lungs and also affect intestines, bones, and joints and other tissues of body. Severe cases may lead to death.

Samacheer Kalvi 9th Science Guide Chapter 22 World of Microbes

Intext Activities

ACTIVITY – 1

Take the root nodules of any pulse or leguminous plant available in your locality. Wash it thoroughly with water. Crush the nodules on a clean glass slide. Add a drop of distilled water to the crushed material on the glass slide. Observe the preparation under compound microscope.

Observation of Symbiotic microbes.

Aim : To observe symbiotic bacteria shape on a clean glass plate.

Materials Required :
1. Root nodules of leguminous plant, Clean glass slides, Water, Distilled water.

Procedure :

  1. Take the root nodules of the leguminous plant.
  2. Wash it thoroughly with water.
  3. Crush the nodules on a clean glass slide.
  4. Add a drop of distilled water to the crushed material on the glass slide.

Observation:

Conclusion :
The structure of symbiotic bacteria is observed in a clean glass plate.
[End of the activity]

Samacheer Kalvi 9th Science Guide Chapter 22 World of Microbes

ACTIVITY – 2

Observe the mosquitoes that are active during the day time. Catch them using an insect net and observe their body and legs. What do you observe? Why are cases of Dengue reported in large numbers during post-monsoon season?

Observation :
Body and legs of Aedes aegypti :
We can find black and white stripes on the bodies and leg.
The white marking in the leg is in the form of a lyre.

High Dengue cases during post-monsoon

  1. Due to the rainy season, conditions like stagnant water favours the mosquitoes to grow in large number.
  2. Thus, a sharp rise in dengue cases are reported. [End of the activity]

Samacheer Kalvi 9th Science Guide Chapter 22 World of Microbes

9th Science Guide World of Microbes Additional Important Questions and Answers

I. Choose the correct answer :

Question 1.
Which one of the following is a symbiotic bacteria?
(a) Azospirillum
(b) Azotobacter
(c) Rhizobium
(d) None of these
Answer:
(c) Rhizobium

Question 2.
The shape of Vibrio cholerae is
(a) Spherical
(b) Spiral
(c) Rod
(d) None of these
Answer:
(b) Spiral

Samacheer Kalvi 9th Science Guide Chapter 22 World of Microbes

Question 3.
……………are the site of protein synthesis in bacteria.
(a) Ribosomes
(b) Chromosomes
(c) Plasmid
(d) Nucleus
Answer:
(a) Ribosomes

Question 4.
Fungi reproduce through …………..
(a) binary fission
(b) budding
(c) spore formation
(d) all of these
Answer:
(d) all of these

Samacheer Kalvi 9th Science Guide Chapter 22 World of Microbes

Question 5.
Which one of the following is not an antibiotic derived from Bacteria?
(a) Cephalosporin
(b) Erythromycin
(c) Bacitracin
(d) Streptomycin
Answer:
(a) Cephalosporin

Question 6.
AIDS is’ a …………… disease.
(a) Endemic
(b) Epidermic
(c) Pandemic
(d) Sporadic
Answer:
(c) Pandemic

Samacheer Kalvi 9th Science Guide Chapter 22 World of Microbes

Question 7.
Fever, sore throat, and choking of air passage are symptoms of ……………
(a) influenza
(b) diphtheria
(c) whooping cough
(d) typhoid
Answer:
(a) influenza

Question 8.
Myxovirus is the causative agent for …………… disease.
(a) common cold
(b) measles
(c) influenza
(d) diarrhoea
Answer:
(c) influenza

Samacheer Kalvi 9th Science Guide Chapter 22 World of Microbes

Question 9.
The symptoms of measles is ……………
(a) eruption of small rashes in skin
(b) redness of eye
(c) pneumonia
(d) all the above
Answer:
(d) all the above

Question 10.
The stages of malarial parasite are developed in the …………… of mosquito
(a) respiratory tract
(b) gastrointestinal tract
(c) intestinal tract
(d) none of these
Answer:
(b) gastrointestinal tract

Samacheer Kalvi 9th Science Guide Chapter 22 World of Microbes

Question 11.
Incubation period of the virus for chikungunya is usually . ……………
(a) 2-12 days
(b) 2-7 days
(c) 4-8 days
(d) 3-9 days
Answer:
(a) 2-12 days

Samacheer Kalvi 9th Science Guide Chapter 22 World of Microbes

Question 12.
The disease that displays Nocturnal periodicity ……………
(a) swine flu
(b) dengue
(c) filaria
(d) influenza
Answer:
(c) filaria

Question 13.
Nasal spray vaccine can be administered to ……………patients.
(a) chikungunya
(b) dengue
(c) influenza
(d) swine flu
Answer:
(d) swine flu

Question 14.
Human Immuno deficiency Virus (HIV) was first isolated by …………..
(a) Robert Koch
(b) Robert Gallo
(c) Ronald Ross
(d) Louis Pasteur
Answer:
(b) Robert Gallo

Samacheer Kalvi 9th Science Guide Chapter 22 World of Microbes

Question 15.
The disease that is eliminated totally by the vaccination process is …………….
(a) chicken pox
(b) Filaria
(c) smallpox
(d) None of these
Answer:
(c) small pox

Question 16.
Among the following, which is belongs to water-borne diseases?
(a) Hepatitis A
(b) Hepatitis B
(c) Influenza
(d) Dengue
Answer:
(a) Hepatitis A

Samacheer Kalvi 9th Science Guide Chapter 22 World of Microbes

Question 17.
Measles vaccine can be administered to the child at the age of ……………
(a) 18-24 months
(b) 15-18 months
(c) 9-12 months
(d) 14th week
Answer:
(c) 9 – 12 months

Question 18.
Mycology is the branch of biology that deals with the study of ……………
(a) algae
(b) virus
(c) bacteria
(d) fungi
Answer:
(d) fungi

Question 19.
The major constituent of vinegar is ……………
(a) citric acid
(b) acetic acid
(c) oxalic acid
(d) hydrochloric acid
Answer:
(b) acetic acid

Samacheer Kalvi 9th Science Guide Chapter 22 World of Microbes

Question 20.
Bacteria involved in curd formation is ……………
(a) Lactobacillus acidophilus
(b) Nitrosomonas
(c) Bacillus ramous
(d) none of the above
Answer:
(a) Lactobacillus acidophilus

Question 21.
The most fetal form of malaria is caused by ……………..
(a) Plasmodium ovale
(b) Plasmodium falciparum
(c) Plasmodium malariae
(d) Plasmodium vivax
Answer:
(b) Plasmodium falciparum

Question 22.
Syphilis is caused by ………………….
(a) Treponema pallidum
(b) Leptospira
(c) Pasteurella
(d) Vibrio cholerae
Answer:
(a) Treponema pallidum

Samacheer Kalvi 9th Science Guide Chapter 22 World of Microbes

Question 23.
Mosquito-borne viral diseases are …………………
(a) malaria and yellow fever
(b) dengue and chikungunya
(c) filariasis and typhus
(d) kala-azar and diphtheria
Answer:
(b) dengue and chikungunya

Question 24.
Which one of the following is a pair of viral disease?
(a) Filariasis, AIDS
(b) Common cold, AIDS
(c) Dysentery, Common cold
(d) Typhoid, Tuberculosis
Answer:
(b) Common cold, AIDS

Samacheer Kalvi 9th Science Guide Chapter 22 World of Microbes

Question 25.
Which of the following disease is spread by animal bite?
(a) Pneumonia
(b) Tuberculosis
(c) Cholera
(d) Rabies
Answer:
(d) Rabies

II. Fill in the blanks :

1. Bacterial cell was covered by a strong cell wall made up of ……………
Answer:
peptidoglycan

2. In bacteria, a small extra chromosomal circular DNA called ………….. is found in the cytoplasm.
Answer:
plasmid

Samacheer Kalvi 9th Science Guide Chapter 22 World of Microbes

3. ………………bacteria live on dead organic matter.
Answer:
Saprophytic

4. Viruses are non-cellular, …………………… parasites.
Answer:
self-replicating

5. Adenovirus is………………….virus.
Answer:
animal

Samacheer Kalvi 9th Science Guide Chapter 22 World of Microbes

6. The cell wall of fungi is made up of ……………… and …………….
Answer:
cellulose, hemicellulose

7. Prions do not contain …………………..
Answer:
Nucleic acid

8. ‘Cry’ protein is produced by the bacteria………………….
Answer:
Bacillus Thuringiensis

9. Yeasts are rich source of …………………..
Answer:
vitamin – B complex

Samacheer Kalvi 9th Science Guide Chapter 22 World of Microbes

10. Vaccines stimulate the body to produce …………………. against the …………………. in the microbes.
Answer:
antibodies, antigen

11. Cholera is a ………… disease
Answer:

12. The interval between infection and first appearance of the diseases is called …………………..period.
Answer:
incubation

13. …………. is the Father of Bacteriology
Answer:
Robert Koch

14. The causative agent (bacteria) of whooping cough is ………….
Answer:
Bordetalla pertussis

Samacheer Kalvi 9th Science Guide Chapter 22 World of Microbes

15. Inflammation of nasal mucosa and pharynx are the symptoms of ………….
Answer:
influenza

16. The most vulnerable age of polio is between ………… years
Answer:
3 – 6

17. Use of ………… drugs kills the stages of malaria parasite.
Answer:
Quinine

Samacheer Kalvi 9th Science Guide Chapter 22 World of Microbes

18. Dengue is known as ………… fever.
Answer:
Break bone

19. Nilavembu kudineer is known to increase…………
Answer:
blood platelet count

20. The process of vaccination was introduced by ……………….
Answer:
Edward Jenner

Samacheer Kalvi 9th Science Guide Chapter 22 World of Microbes

21. The hyphae with branches form a complex network called ……………
Answer:
mycelium

22. First antibiotic …………… was developed by ……………
Answer:
penicillin, Alexander Fleming

23. Baker’s yeast is …………….
Answer:
the yeast used in baking bread

24. The two non-symbiotic nitrogen fixing bacteria are ……………and ……………
Answer:
cyanobacteria, Azotobacter

III. Match the following :

I.

1. World Anti-Tuberculosis day a) 7th April
2. World Malaria day b) 1st December
3. World Health day c) 24th March
4. World AIDS day d) 25th April

Answer:
1 – c, 2 – d, 3 – a, 4 – b II.

Samacheer Kalvi 9th Science Guide Chapter 22 World of Microbes

II.

1. Rhizobium a) Phosphorus
2. Azotobacter b) Soil bacterium
3. Mycorrhizae c) Anabaena
4. Azolla d) Antifungal compounds

Answer:
1 – b, 2 – d, 3 – a, 4 – c

III.

1. Saccharomyces cerevisiae a) Biofertilizers
2. Mycorrhizae b) Organic acids
3. Aspergillus Niger c) Fermented beverages
4. Bacillus Megaterium d) Curing of tobacco leaves

Answer:
1 – c, 2 – a, 3 – b, 4- d

IV.

Diseases Incubation Period
1. Dengue a) 2-12 days
2. Chikungunya b) 5-6 days
3. Filaria c) 4 2-7 days
4. Avian Influenza d) 8-16 months

Answer:
1 – b, 2 – a, 3 – d, 4- c

Samacheer Kalvi 9th Science Guide Chapter 22 World of Microbes

V.
Samacheer Kalvi 9th Science Guide Chapter 22 World of Microbes 6
Answer:
Samacheer Kalvi 9th Science Guide Chapter 22 World of Microbes 7

IV. State whether True or False. If false write the correct statement

1. Virions are the smallest among the infective agents.
Answer:
True.

2. Viruses are devoid of cellular organelles like ribosomes^ mitochondria, etc.
Answer:
True.

3. Prions are found in neurons and are cone-shaped.
Answer:
False.
Correct statement: Prions are found in neurons and are rod-shaped.

Samacheer Kalvi 9th Science Guide Chapter 22 World of Microbes

4. In human beings, antibodies are used to cure infectious diseases like cholera, typhoid, etc.
Answer:
False.
Correct statement: In human beings, antibodies are used to control infectious diseases like cholera, typhoid, etc.

5. An infection develops when these pathogens enter the human body.
Answer:
True.

6. Airborne diseases are caused by fungi.
Answer:
False.
Correct statement: Airborne diseases are caused by bacteria and viruses.

7. Influenza commonly occurs during adult age.
Answer:
False.
Correct statement: Influenza commonly occurs during childhood.

Samacheer Kalvi 9th Science Guide Chapter 22 World of Microbes

8. Malaria is caused by the fungal parasite plasmodium.
Answer:
False.
Correct statement: Malaria is caused by the protozoan parasite Plasmodium.

9. Filaria is transmitted by the bite of an infected Culex mosquito.
Answer:
True.

10. Swine flu spreads through the air by an acute respiratory virus.
Answer:
True.

11. Hepatitis A causes cirrhosis of the liver.
Answer:
False.
Correct statement: Hepatitis B causes cirrhosis of the liver.

Samacheer Kalvi 9th Science Guide Chapter 22 World of Microbes

12. Oral polio vaccine is a killed vaccine.
Answer:
False
Correct statement: Oral polio vaccine is a Live vaccine.

13. Glycogen and oil globules are stored forms of food in fungi.
Answer:
True.

14. One of the differences between virus and viroid is the presence of protein coat in viroid and its absence in the virus.
Answer:
False.
Correct statement: One of the differences between virus and viroid is the presence of protein coat in vim:: and its absence in viroid.

Samacheer Kalvi 9th Science Guide Chapter 22 World of Microbes

V. Assertion and Reason :

Mark the correct answer :
(a) If both Assertion and Reason are true and Reason is the correct explanation of Assertion.
(b) If both Assertion and Reason are true but the reason is not the correct explanation of assertion.
(c) If Assertion is true but Reason is false.
(d) If Assertion is false but Reason is true.

Question 1.
Assertion: Some bacteria may be non-motile.
Reason: Bacteria have a special structure called flagella which are found on cell surfaces.
Answer:
(d) Assertion is false but Reason is true

Question 2.
Assertion : Bacillus Thuringiensis is a biocontrol agent.
Reason : It produces a protein called ‘cry protein’ which kills insect larva.
Answer:
(a) Both assertion and reason are true and Reason is the correct explanation of Assertion

Samacheer Kalvi 9th Science Guide Chapter 22 World of Microbes

Question 3.
Assertion : Cancer is a non-infectious disease.
Reason : Cancer is caused by external factors like pathogens invading the body.
Answer:
(c) Assertion is true but Reason is false
Reason : Cancer is caused by internal factors like the malfunctioning of organs.

Question 4.
Assertion : An infection develops when pathogens enter the human body.
Pathogen enters the human body through contaminated air, water, food, soil, physical contact etc.
Answer:
(a) Both assertion and reason are true and Reason is the correct explanation of Assertion

Question 5.
Assertion : Chikungunya is transmitted in humans by the bite of infected Aedes aegypti mosquito during the day time.
Reason : Chikungunya is caused by Rotavirus.
Answer:
(c) Assertion is true but Reason is false]
Reason : Chikungunya is caused by a single-stranded RNA virus.

Samacheer Kalvi 9th Science Guide Chapter 22 World of Microbes

VI. Expand the following :

  1. CJD
  2. TT
  3. OPV
  4. HAY
  5. AIDS
  6. MMR

Answer:

  1. CJD – Creutzfeldt -Jakob Disease
  2. TT – Tetanus Toxoid
  3. OPV – Oral Polio Vaccine
  4. HAV – Hepatitis A Virus
  5. AIDS – Acquired Immuno Deficiency Syndrome
  6. MMR – Mumps, Measles, Rubella

Samacheer Kalvi 9th Science Guide Chapter 22 World of Microbes

VII. Define the following :

1. Disease, 2. Infection, 3. Antibiotics, 4. Toxin, 5. Vector
Answer:
1. Disease:
The disease can be defined as an impairment or malfunctioning of the normal state of the living organism that disturbs or modifies the performance of vital functions of the body.

2. Infection:
Infection is the entry, development, or multiplication of an infectious agent in the human body or animals.

3. Antibiotics:
Antibiotics are metabolic products of microorganisms whose very low concentrations are inhibitory or detrimental to other microbes.

4. Toxin :
The poisonous substances secreted by pathogens that cause diseases are called toxins.

5. Vector:
Vector is an agent that acts as an intermediate carrier of the pathogen.

Samacheer Kalvi 9th Science Guide Chapter 22 World of Microbes

VIII. Answer in one or two sentences :

Question 1.
What is bacteria?
Answer:
Bacteria are microscopic, single-celled prokaryotic organisms without a nucleus and other cell organelles. >

Question 2.
Differentiate Parasites and Saprophytes.
Answer:
Parasites :
Fungi living on living hosts.

Saprophytes :
Fungi living on dead organic matter.

Samacheer Kalvi 9th Science Guide Chapter 22 World of Microbes

Question 3.
What is the incubation period?
Answer:
1. The interval between infection and the first appearance of the diseases is called the incubation period.
2. It may vary from few hours to several days.

Question 4.
Differentiate Exotoxins and Endotoxins.
Answer:
Exotoxins :
There are directly secreted by the pathogens.

Endotoxins :
There are released by the disintegration of pathogens.

Question 5.
Why is dengue also known as break-bone fever?
Answer:
The name break bone fever was given because contortions caused intense joint and muscle pain.

Samacheer Kalvi 9th Science Guide Chapter 22 World of Microbes

Question 6.
What is an immunization?
Answer:
Immunization is a process of developing resistance to infections by administration of antigens (or) antibodies. .

Question 7.
What is TAB?
Answer:
TAB is a combined vaccine for Typhoid, Paratyphi A and Paratyphi B.

Question 8.
Name two diseases transmitted by Aedes aegypti mosquito?
Answer:

  1. Chikungunya,
  2. Dengue.

Question 9.
What is known as reservior of infection? Give two example.
Answer:
Reservoir of infection are breeding ground for pathogens. E.g. Water, soil.

Samacheer Kalvi 9th Science Guide Chapter 22 World of Microbes

Question 10.
Differentiate signs and symptoms of disease.
Answer:
Signs :
Signs of disease provide information about particular disease.

Symptoms :
Symptoms are recognizable signs of infectious disease.

Question 11.
Name one disease that is transmitted by houseflies. Mention their causative pathogen.
Answer:
Cholera – Vibrio cholerae (pathogen)

Question 12.
Name the scientist who first discovered penicillin antibiotic. Can you name any other known antibiotic?
Answer:

  1. Penicillin was discovered by Alexander Fleming.
  2. Other known Antibiotic – Tetracycline.

Samacheer Kalvi 9th Science Guide Chapter 22 World of Microbes

Question 13.
A baby is suffering from diarrhoea, while other babies in the same locality do not.
Mention the possible causes that you think. What would be the possible solutions for this? »
Answer:

  1. Cause for Diarrhoea: Contaminated food (or) water.
  2. Possible solutions: Hygienic sanitary condition, Use of Oral Rehydration Solution (ORS).

Question 14.
Sanjay had an attack of chickenpox and has just recovered. The health officer of his locality says that the disease would not occur again for him. What would be the reason for this?
Answer:
While Chicken Pox attacks the first time, it develops immunity for the rest of life.

IX. Short answer questions :

Question 1.
Briefly explain the reproduction of fungi using a flow chart.
Answer:
Samacheer Kalvi 9th Science Guide Chapter 22 World of Microbes 8

Samacheer Kalvi 9th Science Guide Chapter 22 World of Microbes

Question 2.
What is an epidemic disease?
Answer:
Epidemic disease is a disease that breaks out and affects large number of people in a particular geographical region and spreads at the same time. E.g. Influenza.

Question 3.
Differentiate between Infectious and Non-Infectious disease.
Answer:
Infections Disease

  1. They are communicable diseases. .
  2. They are caused by external factors. Invading of pathogens such as bacteria, virus, vectors, parasites etc.
    E.g. Cholera, Malaria, Chickenpox.

Non-infectious disease

  1. They are non-communicable diseases
  2. They are caused by internal factors.
    • Malfunctioning of organs,
    • Genetic causes,
    • Hormonal imbalance and
    • Defective Immune system
      E.g. Cancer, Diabetes.

Samacheer Kalvi 9th Science Guide Chapter 22 World of Microbes

Question 4.
What causes illness?
Answer:
An illness is casual due to a specific infectious agent, capable of being directly or indirectly transmit infection from person to person, animal to animal or from the environment (air, water & food) and insects.

Question 5.
How are respiratory tract infections acquired?
Answer:
Respiratory tract infections are acquired by inhaling air containing the pathogen that is transmitted through droplets caused by cough (or) sneeze, dust, spores, etc.

Question 6.
Name the different species of protozoa plasmodium.
Answer:
The different species of plasmodium are –

  1. Plasmodium vivax
  2. Plasmodium malariae
  3. Plasmodium falciparum
  4. Plasmodium ovale.

Samacheer Kalvi 9th Science Guide Chapter 22 World of Microbes

Question 7.
List the precautionary measures to avoid Avian Influenza.
Answer:
Prevention and Control:

  • Avoid open-air markets where infected birds are sold.
  • Avoid contact and consumption of infected birds.
  • Proper cleaning and cooking of poultry.

Question 8.
Mention the symptoms of poliomyelitis.
Answer:
Symptoms of poliomyelitis :

  • Paralysis of limbs and muscles.
  • Difficulty in walking.

Question 9.
When Malar, who is suffering from high fever, muscle, and joint pain, undergoes a blood test, it was found that her blood platelet was decreased.
a. What disease is Malar infected with?
b. How is the disease transmitted?
c. How can it be treated?
Answer:
a. Dengue fever.
b. Dengue was caused by a virus which is transmitted by the Aedes aegypti mosquito.
c. Treatment:

  • Administer paracetamol to reduce fever and body ache.
  • Increase intake of fluid to increase immunity.
  • Complete rest for rehabilitation.

Samacheer Kalvi 9th Science Guide Chapter 22 World of Microbes

Question 10.
How is typhoid prevented and treated?
Answer:
Prevention:

  • Contaminated food by flies-and dust should be prevented.
  • Basic sanitation and hygienic practices should be improved.

Treatment:
Typhoid should be treated with antibiotic drugs.

Question 11.
We are advised to take bland and nutritious food when we are sick. What is the reason?
Answer:

  • Bland and nutritious food are soft, less spicy and low in fibre.
  • They are easy digestable and energy giving food. . . .
    Thus, sick person can restore his immunity through bland and nutritious food.

Question 12.
How will you differentiate Hepatitis A from Hepatitis B?
Answer:

Hepatitis A Hepatitis B
1. Caused by Hepatitis A virus (HAV) 1. Caused by Hepatitis B virus
2. Transmitted through

  1. Contaminated water
  2. Food
  3. Oral route
2. Transmitted through contact (from infected person to a healthy person)

  1. Sexual.
  2. Blood contact.
  3. By surgical equipment (infected needles and syringes).
  4. Material (foetal transmission from infected mother to the foetus).
3. Liver is affected in Jaundice (Yellow fever) 3. Cirrhosis of liver.

Samacheer Kalvi 9th Science Guide Chapter 22 World of Microbes

X. Long Answer question : 

Question 1.
Enumerate the living and non-living characters of virus.
Answer:
1. Living characters of viruses:

  • They have nucleic acid DNA or RNA i.e., the genetic material that can replicate.
  • They can multiply in the living cells of the host.
  • They can attack specific hosts.

2. Non-living characters of viruses:

  • Viruses remain as inert material outside their hosts.
  • They are devoid of the cell membrane and cell wall.
  • They are devoid of cellular organelles like ribosomes, mitochondria, etc.
  • They can be crystallised.

Question 2.
Discuss how diseases are categorised.
Answer:
Disease can be catagorized on the basis of:

(i) Extent of occurrence
(ii) Infectious nature
(iii) Type of pathogen
(iv) Transmitting Agent

(i) Extent of occurrence :

  • Endemic diseases – Found in the certain geographical area affects the fewer number of people, E.g. Goitre in sub = Himalayan region.
  • Epidemic diseases – Disease which breaks out and affects a large number of people in a particular geographical region and spreads at the same time. E.g. Influenza.
  • Pandemic disease – Widely distributed on a global scale. E.g. AIDS.
  • Sporadic disease – Occasional occurrence of a disease. E.g. Cholera and malaria.

(ii) Infectious nature:

1. Infectious disease are communicable diseases. Caused by external factors pathogenic organisms. E.g. Chickenpox and malaria.

2. Non-Infectious disease:

  • Non-communicable diseases.
  • Caused by internal factors like :
  • Malfunctioning of organs and genetic causes. Hormonal imbalance and immune system defect. E.g. Diabetes, coronary heart diseases, obesity, cancer, goitre etc.

(iii) Types of pathogen :

  • Bacterial diseases
  • Viral diseases
  • Fungal diseases
  • Protozoan diseases

(iv) Transmitting agent:

  • Airborne diseases: Due to continuous inhalation of contaminated air.
    E.g. Tuberculosis.
  • Waterborne diseases: Microbes present in the contaminated water cause various infectious diseases.
    E.g. Cholera, typhoid, etc.
  • Vector-borne diseases: Vector is an agent that acts as an intermediate carrier of the pathogen.
    E.g. Malaria, filaria, chikungunya.

Samacheer Kalvi 9th Science Guide Chapter 22 World of Microbes

Question 3.
Discuss the strategies to adopt to prevent diseases transmitted through mosquitoes.
Answer:

  • Prevention of mosquito bites by using mosquito nets mosquito screens, mosquito repellents, and ointments.
  • Providing adequate sanitation, underground wastewater disposable system, and drainage of stagnant water to eliminate the breeding places.
  • Avoid the collection of water in any uncovered container such as water tanks, pots, flowers, discarded tyres, etc.
  • Spraying oil on stagnated water bodies to control mosquito larvae.
  • Adult mosquitoes can be killed by spraying insecticides.
  • Application of citronella oil (or) eucalyptus oil on the exposed skin.

Question 4.
Amal, a thirteen-year-old boy is suffering from fever, headache, body pain, vomiting, and diarrhoea. He finds it difficult to breathe.

  1. Diagnose the disease.
  2. What is the causative agent?
  3. What prevention and control measures can be taken?

Answer:

  1. Diagnosed Disease: Swine flu.
  2. Causative agent: InfluerKa virus H1N1
  3. Prevention and control:
    • Administration of nasal spray vaccine.
    • Avoiding close contact with a person suffering from the flu.
    • Intake of water and fruit juices will help prevent dehydration.
    • Plenty of rest will help the body fight infection.
    • Always wash hands regularly and practice good hygiene.

Question 5.
Name the causative agent of typhoid in humans. How does the pathogen gain entry into the human body? Write the diagnostic symptoms and mention the organ that is affected in severe cases.
Answer:

  • Causative agent of typhoid: Salmonella Typhi (Bacteria)
  • The entry of Pathogen: Food and water contaminated by the faeces of an infected person through houseflies.
  • Diagnostic symptoms: Fever, weakness, and vomiting.
  • Affected organ: Small Intestine.

Samacheer Kalvi 9th Science Guide Chapter 22 World of Microbes

Question 6.
Some human diseases are transmitted only when the blood of a patient comes in close contact with the blood of a healthy person. In one such disease, there is a progressive decrease in WBC of the patient.

  1. Name the disease and its causative agent.
  2. Name the type of WBC affected during infection.
  3. How does the blood of a patient come in contact with the blood of a healthy patient?
  4. Suggest three methods that help in preventing such infection.

Answer:

  1. Disease Name Causative agent: AIDS (Acquired Immuno Deficiency Syndrome).
  2. Affected WBC type: Human Immunodeficiency Virus (HIV)
  3. Contact of blood: Lymphocytes (T-lymphocytes)
  4. Prevention methods: Transfusion of unscreened blood (blood contact).
    • Usage of disposable syringes and needles.
    • Screening of blood before blood transfusion.
    • Avoid sharing shaving blades/razors.

Samacheer Kalvi 9th Science Guide Chapter 24 Environmental Science

Tamilnadu State Board New Syllabus Samacheer Kalvi 9th Science Guide Pdf Chapter 24 Environmental Science Text Book Back Questions and Answers, Notes.

Tamilnadu Samacheer Kalvi 9th Science Solutions Chapter 24 Environmental Science

9th Science Guide Environmental Science Text Book Back Questions and Answers

Samacheer Kalvi 9th Science Guide Chapter 11 Atomic Structure

I. Choose the correct answer:

Question 1.
All the factors of biosphere which affect the ability of organisms to survive and reproduce are called as ………………
(a) biological factors
(b) abiotic factors
(c) biotic factors
(d) physical factors
Answer:
(c) biotic factors

Question 2.
The ice sheets from the north and south poles and the icecaps on the mountains, get converted into water vapour through the process of ………………..
(a) evaporation
(b) condensalion
(c) sublimation
(d) infiltration
Answer:
(c) sublimation

Samacheer Kalvi 9th Science Guide Chapter 11 Atomic Structure

Question 3.
The atmospheric carbon dioxide enters into the plants through the process of ………………..
(a) photosynthesis
(b) assimilation
(c) respiration
(d) decomposition
Answer:
(a) photosynthesis

Question 4.
Increased amount of ……………….. in the atmosphere, results in greenhouse effect and global warming.
(a) carbon monoxide
(b) sulphur dioxide
(c) nitrogen dioxide
(d) carbon dioxide
Answer:
(d) carbon dioxide

Samacheer Kalvi 9th Science Guide Chapter 11 Atomic Structure

II. Match the following:

Question 1.

Microorganism Role played
Nitrosomonas Nitrogen fixation
Azotobacter Ammonification
Pseudomonas species Nitrification
Putrefying bacteria Denitrification

Answer:

Microorganism Role played
Nitrosomonas Nitrification
Azotobacter Nitrogen fixation
Pseudomonas species Denitrification
Putrefying bacteria Ammonification

Samacheer Kalvi 9th Science Guide Chapter 11 Atomic Structure

III. Say true or false. Correct the false statements :

1. Nitrogen is a greenhouse gas.
Answer:
False.
Correct statement: Carbon dioxide is a greenhouse gas.

2. Poorly developed root is an adaptation of mesophytes.
Answer:
False,
Correct statement: Poorly developed root is an adaptation of Hydrophtes.

3. Bats are the only mammals that can fly.
Answer:
True

Samacheer Kalvi 9th Science Guide Chapter 11 Atomic Structure

4. Earthworms use the remarkable high frequency system called echoes.
Answer:
False.
Correct statement: Buts use the remarkable high frequency system called echoes.

5. Aestivation is an adaptation to overcome cold condition.
Answer:
False.
Correct statement: Aestivation is an adaptation to overcome condition.

Samacheer Kalvi 9th Science Guide Chapter 11 Atomic Structure

IV. Give reason for the following.

Question 1.
Roots grow very deep and reach the layers where water is available. Which type of plants develop the above adaptation? Why?
Answer:
Xerophytes have well developed roots.
Reason: They grow in dry habitat where water is scarcely available.

Question 2.
Why steamlined bodies and presence of setae is considered as adaptations of earthworm?
Answer:

  • Streamlined bodies of earthworm helps to live in narrow burrows underground and for easy penetration into the soil.
  • Seine helps earthworm to move through the soil and provide anchor in the burrows.

Samacheer Kalvi 9th Science Guide Chapter 11 Atomic Structure

Question 3.
Why is it impossible for all farmers to construct farm ponds it in their fields?
Answer:

  • Farm ponds reduce water flow to other tanks and ponds situated in lower-lying areas.
  • Ponds occupy a large portion of farmer’s lands.

V. Answer briefly:

Question 1.
What are the two factors of biosphere?
Answer:
The biosphere is the part of the earth where life exists. All resources of the biosphere can be grouped into two major categories namely:

  1. Biotic or living factors which include plants, animals and all other living organisms.
  2. Abiotic or non-living factors which include all factors like temperature, pressure, water, soil, air and sunlight which affect the ability of organisms to survive and reproduce.

Question 2.
How do human activities affect nitrogen cycle?
Answer:
Human activities,

  • alters the biodiversity
  • changes the food web structure
  • destroys the general habitat.

Samacheer Kalvi 9th Science Guide Chapter 11 Atomic Structure

Question 3.
What is adaptation?
Answer:
Any feature of an organism or its part that enables it to exist under conditions of its habitat is called adaptation.

Question 4.
What are the challenges faced by hydrophytes in their habitat?
Answer:
Challenges faced by hydrophtes:

  • More water availability than needed.
  • Damaging of water body by water current.
  • Regular change of water level.
  • Maintenance of buoyancy in water.

Question 5.
Why is it important to conserve water?
Answer:
Importance of water conservation:

  • It creates a more efficient use of water resources.
  • It ensures that we have enough usable water.
  • It helps in decreasing water pollution.
  • It helps in increasing energy saving.

Samacheer Kalvi 9th Science Guide Chapter 11 Atomic Structure

Question 6.
List some of the ways in which you could save water in your home and school?
Answer:
We could save water by

  • Using low flow taps.
  • Using recycled water for lawns.
  • Repairing the leaks in the taps.
  • Recycling (or) reusing water wherever it is possible.

Question 7.
What are the uses of recycled water?
Answer:
Uses for recycled water:
Agriculture, Landscape, Public parks, Golf course irrigation, Cooling water for power plants and oil refineries, Toilet flushing, Dust control, and Construction activities.

Question 8.
What is IUCN? What is the vision of IUCN?
Answer:
IUCN: International Union for Conservation of Nature and Natural Resources.
VISION: A just world that values and conserves nature.

Samacheer Kalvi 9th Science Guide Chapter 11 Atomic Structure

VI. Answer in detail:

Question 1.
Describe the processes involved in the water cycle.
Answer:
Water cycle or hydrological cycle is the continuous movement of water on earth. In this process, water moves from one reservoir to another, from river to ocean or from ocean to the atmosphere by processes such as evaporation, sublimation, transpiration, condensation, precipitation, surface runoff and infiltration, during which water converts itself to various forms like liquid, solid and vapour.

  • Evaporation: Water evaporates from the surface of the earth and water bodies such as the oceans, seas, lakes, ponds and rivers turn into water vapour.
  • Sublimation: Ice sheets and ice caps from north and south poles, and icecaps on mountains get converted into water vapour directly, without converting into liquid.
  • Transpiration: Transpiration is the process by which plants release water vapour to atmosphere through small pores in leaves and stems.
  • Condensation: At higher altitudes, the temperature is low. The water vapour present there condenses to form very tiny particles of water droplets. These particles come close together to form clouds and fog.
  • Precipitation: Due to change in wind or temperature, clouds combine to make bigger droplets, and pour down as precipitation(rain). Precipitation includes drizzle, rain, snow and hail.
  • Runoff: As the water pours down, it runs over the surface of earth. Runoff water combines to form channels, rivers, lakes and ends up into seas and oceans.
  • Infiltration: Some of the precipitated water moves deep into the soil. Then it moves down and increases the groundwater level.
  • Percolation: Some of the precipitated water flows through soil and porous or fractured rock. Infiltration and percolation are two related but different processes describing the movement of water through soil.

Samacheer Kalvi 9th Science Guide Chapter 11 Atomic Structure

Question 2.
Explain carbon cycle with the help of a flow chart.
Answer:
Samacheer Kalvi 9th Science Guide Chapter 24 Environmental Science-1

Question 3.
List out the adapatations of xerophytes.
Answer:
The conditions that lead to adaptation of plants in a dry habitat are;

  1. To absorb as much water as they can get from their surroundings.
  2. To retain water in their organs for a very long time.
  3. To reduce the transpiration rate.
  4. To reduce the consumption of water.

Adaptations of xerophytes:

  1. They have well-developed roots. Roots grow very deep and reach the layers where water is available as in Calotropis.
  2. They store water in succulent water-storing parenchymatous tissues, e.g. Opuntia, Aloe vera.
  3. They have small-sized leaves with a waxy coating, e.g. Acacia. In some plants, leaves are modified into spines, e.g. Opuntia.
  4. Some of the xerophytes complete their life cycle within a very short period when sufficient moisture is available.

Samacheer Kalvi 9th Science Guide Chapter 11 Atomic Structure

Question 4.
How does a bat adapt itself to its habitat?
Answer:
Adaptations of BAT:

  • Mostly, bats live in caves, which provide protection during the day from most predators and maintain a stable temperature.
  • Bats are active at night. This, is a useful adaptation for them, as flight requires a lot of energy during day.
  • By Hibernation, bats reduce body temperature with lowered metabolic rate during winter.
  • Bats let their internal temperature reduce during rest.
  • Bats use echolocation (High frequency ultrasonic sound waves) to identify and locate the prey.

Question 5.
What is water recycling? Explain the conventional wastewater recycling treatment?
Answer:
Water Recycling: Water recycling is reusing treated wastewater for beneficial purposes
such as agricultural and land irrigation, industrial processes, etc.
Conventional wastewater recycling treatment : Conventional wastewater treatment consists of combination of physical, chemical and biological processes involving the following stages.
Samacheer Kalvi 9th Science Guide Chapter 24 Environmental Science-2

Samacheer Kalvi 9th Science Guide Chapter 11 Atomic Structure

Intext Activities

ACTIVITY – 1

Create your own water cycle.

Take a small container and place it in the middle of the large bowl. Fill water in the large container and cover it with plastic wrap. Fasten the plastic wrap around the rim of the large container with the rubber band. Place a stone on the top of the plastic wrap. Keep this under sun for few hours. Record your observation.

Aim :
To understand utilisation and recycling of water.

Materials:
A large transparent bowl, plastic wrap, a stone, a smaller container and a rubber band. Procedure:

  1. The small container is placed in the middle of the large bowl. Water is filled in the large container and it is covered with plastic wrap.
  2. The plastic wrap is fastened around the rim of the large container with the rubber band.
  3. The stone is placed on the top of the plastic wrap.
    This is placed under the sun for few hours.

Observation :

  1. When we have a close look at the plastic wrap, water droplets would be formed in the surface of plastic wrap. Thus, can conclude there is condensation process.
  2. The level of the water in bowl is reduced. It suggests that a part of water is evaporated.
  3. After sometime, the droplets on the plastic wrap drip into the bowl which indicates the phenonmenon of Precipitation.

Conclusion :
In this activity, the processes such as condensation, evaporation and precipitation have been demonstrated.
[End of the activity]

Samacheer Kalvi 9th Science Guide Chapter 11 Atomic Structure

9th Science Guide Environmental Science Additional Important Questions and Answers

I. Choose the correct answer :

Question 1.
Which of the following is not an adaptation of hydrophytes?
(a) poorly developed root system
(b) reduced plant body
(c) water storing parenchymatous tissues
(d) finely divided submerged leaves
Answer:
(c) water storing parenchymatous tissues

Question 2.
In some xerophytes, leaves are modified into spines as an adaptation ……………..
(a) to reduce transpiration rate
(b) to store water
(c) to reduce consumption of water
(d) all of the above
Answer:
(d) all of the above

Samacheer Kalvi 9th Science Guide Chapter 11 Atomic Structure

Question 3.
Identify the incorrect statement with respect to adaptations of earthworm.
(a) Earthworm has a steam lined body with no antennae or fins.
(b) Each segment of earthworm has setae.
(c) Many earthworms become inactive in a process called hibernation, during winter season.
(d) Earthworms remain in its burrow during day time, to avoid sunlight.
Answer:
(c) Many earthworms become inactive in a process called hibernation during, winter season

Question 4.
Which of the following is one of the strategies to conserve water?
(a) Water recycling %
(b) Using large overhead watSr tanks
(c) Increasing the number of bore wells
(d) Watering the plants using hose.
Answer:
(a) Water recycling

Question 5.
Specific constituents such as nitrogen, phosphorus, suspended solids and heavy metals found in the wastewaer are removed during …………….. treatment of water recycling process.
(a) primary
(b) secondary
(c) tertiary
(d) none of the above
Answer:
(c) tertiary

Samacheer Kalvi 9th Science Guide Chapter 11 Atomic Structure

Question 6.
Free-living soil bacteria such as Pseudomonas sp. are responsible for the ……………..process in the nitrogen cycle.
(a) ammonification
(b) nitrogen fixation
(c) nitrification
(d) denitrification
Answer:
(d) denitrification

Question 7.
Environmental science provides holistic knowledge about ……………..
(a) Natural processes
(b) Effects of human interventions
(b) Solutions to environmental issues
(d) All the above
Answer:
(d) All the above

Question 8.
Which one the following is not an abiotic factor?
(a) water
(b) air
(c) soil
(d) None of these
Answer:
(d) None of these

Samacheer Kalvi 9th Science Guide Chapter 11 Atomic Structure

Question 9.
The process of water cycle that related with the plants is called …………………
(a) Percolation
(b) Evaporation
(c) Transpiration
(d) Precipitation
Answer:
(c) Transpiration

Question 10.
Rain is due to the process of ………………..
(a) Condensation
(b) Precipitation
(b) Sublimation
(d) Run off
Answer:
(b) Precipitation

Question 11.
…………… is the primary nutrient, important for survival of all living organisms.
(a) Nitrogen
(b) Carbon
(c) Hydrogen
(d) Oxygen
Answer:
(a) Nitrogen

Samacheer Kalvi 9th Science Guide Chapter 11 Atomic Structure

Question 12.
The bacteria present in the root nodules of leguminous plants is .
(a) Nitrobacter
(b) Rhizobium
(c) Pseudomonas sp
(d) Nitrosomonas
Answer:
(b) Rhizobium

Question 13.
In the Nitrification process, the ammonium compounds are oxidised to soluble……………………….
(a) Ammonia
(b) Urea
(c) Nitrites
(d) Nitrates
Answer:
(d) Nitrates

Samacheer Kalvi 9th Science Guide Chapter 11 Atomic Structure

Question 14.
The atmospheric carbon dioxide enters into the plants through the process of
photosynthesis to form
(a) Proteins
(b) Carbohydrates
(c) Water
(d) Carbon monoxide
Answer:
(b) Carbohydrates

Question 15.
Carbon dioxide is also returned to atmosphere through ……………………..
(a) Decomposition of dead organic matter
(b) Burning fossil fuels
(c) Volcanic activities
(d) All the above
Answer:
(d) All the above

Question 16.
The plants that has air chambers is ……………..
(a) Wolffia
(b) Opuntia
(c) Eichhomia
(d) Acacia
Answer:
(c) Eichhornia

Samacheer Kalvi 9th Science Guide Chapter 11 Atomic Structure

Question 17.
Which plant is called as “Cindrella of the plant kingdom”?
(a) Hydrilla
(b) Water hyacinth
(c) Calotropis
(d) Aloevera
Answer:
(b) Water hyacinth

Question 18.
Root caps is a characteristic adaptation of ………………….
(a) Xerophytes
(b) Hydrophytes
(c) Mesophytes
(d) All the above
Answer:
(c) Mesophytes

Question 19.
The presence of ………….. in leaves traps the moisture and lessens water loss inMesophytes.
(a) Waxy Cuticle
(b) stomata
(c) stalk
(d) None of these
Answer:
(a) Waxy Cuticle

Samacheer Kalvi 9th Science Guide Chapter 11 Atomic Structure

Question 20.
…………………. supports and controls movements during flight of a bat.
(a) Forelimbs
(b) Hind limbs
(c) Tail
(d) Muscles
Answer:
(c) Tail

Question 21.
Find the incorrect statement
(a) Vermicompost is prepared by using earthworms
(b) Vermicompost decomposes the plant and animal waste
(c) Vermicompost is an inorganic compound
(d) Vermicompost contains water soluble nutrients.
Answer:
(c) Vermicompost is an inorganic compound

Question 22.
World Water Day is celebrated on …………………..
(a) 22nd February
(b) 22nd March
(c) 5th June
(d) 03rd December
Answer:
(b) 22nd March

Samacheer Kalvi 9th Science Guide Chapter 11 Atomic Structure

Question 23.
Which one of the following is not an advantage of farm ponds?
(a) Reduce soil erosion
(b) Recharge ground water
(c) Reduce water flow to other parts
(d) Improve drainage
Answer:
(c) Reduce water flow to other parts

Question 24.
Biological oxidation is the method is used in ……………….
(a) Primary Treatment
(b) Secondary Treatment.
(c) Tertiary Treatment
(d) None of these
Answer:
(b) Secondary Treatment

Samacheer Kalvi 9th Science Guide Chapter 11 Atomic Structure

Question 25.
The wastes removed in tertiary treatment are ………………
(a) Suspended solids
(b) Biodegradable organic matter
(c) Inorganic substances
(d) All of these
Answer:
(c) Inorganic substances

Question 26.
India accounts for …………………% of all recorded species.
(a) 2-4%
(b) 5-6%
(c) 6-7%
(d) 7-8%
Answer:
(d) 7 – 8%

Samacheer Kalvi 9th Science Guide Chapter 11 Atomic Structure

II. Fill in the blanks :

1. …………………is the study of patterns, processes in the natural world and their modifications
by human activities.
Answer:
Environmental Science

2. Biosphere is a …………………. and …………………and system.
Answer:
dynamic, stable

3. Cyclic flow of nutrients between non-living and living factors of the environment are termed as ……………. cycle.
Answer:
Biogeochemical

Samacheer Kalvi 9th Science Guide Chapter 11 Atomic Structure

4. …………………is the reverse of vapourisation.
Answer:
Condensation

5. Atmosphere is a rich source of ………………….
Answer:
Nitrogen

6. The blue-green algae that take part in nitrogen fixation is also called ………………..
Answer:
Cyanobacteria

Samacheer Kalvi 9th Science Guide Chapter 11 Atomic Structure

7. …………………….. animals convert plant proteins into animal proteins.
Answer:
Herbivorous

8. Carnivorous animals synthesize …………………….. from their food.
Answer:
Protein

9. Charcoal, diamond and graphite are …………………….. forms of carbon.
Answer:
Elemental

Samacheer Kalvi 9th Science Guide Chapter 11 Atomic Structure

10. All living organisms are made up of carbon-containing molecules like …………………….. and ………………………
Answer:
Proteins, nucleic acids

11. Floating leaves have long …………………….. to enable the leaves move up and down in response to changes in water level.
Answer:
Leaf stalks

12. …………………….. is the plant in which leaves are modified into spines.
Answer:
Opuntia

13. The function of stomata in leaves of mesophytes is to prevent ………………………
Answer:
Transpiration

14. In bats, the excessive heat absorption dining the day is caused by ……………………..
Answer:
Patagium

Samacheer Kalvi 9th Science Guide Chapter 11 Atomic Structure

15. In bats modified forelimbs serve as ……………..
Answer:
Wings

16. …………………….. of hind limbs in bat provides a tight grasp when the animals are suspended upside down.
Answer:
Tendons

17. Bats are …………………….. blooded animals
Answer:
warm

18. Earthworm belongs to Phylum . ……………………..
Answer:
Annelida

19. Moist skin in earthworm helps in …………………….. of blood.
Answer:
Oxygenation

Samacheer Kalvi 9th Science Guide Chapter 11 Atomic Structure

20. The theme for World Water Qay 2018 is ………………………
Answer:
Nature for water

21. The microorganism used in file secondary treatment must be separated from treated wastewater by ……………………..
Answer:
Sedimentation

22. There are …………………….. globally identified biodiversity hotspots in India.
Answer:
Four

23. IUCN was founded on …………………….. at Gland, Switzerland.
Answer:
5th October 1948

Samacheer Kalvi 9th Science Guide Chapter 11 Atomic Structure

III. Match the following :

Question 1.

Water cycle Application of fertilizers
Nitrogen cycle Sunlight
Carbon cycle Deforestation
Abiotic factor Volcanic activities

Answer:

Water cycle Deforestation
Nitrogen cycle Application of fertilizers
Carbon cycle Volcanic activities
Abiotic factor Sunlight

Question 2.

XeroLyïtes Broad and thin leaves
Mesophytes Reducedjplant body
Hydrophytes Water hyacinth
Green manure Small sized leaves

Answer:

XeroLyïtes Small sized leaves
Mesophytes Broad and thin leaves
Hydrophytes Reducedjplant body
Green manure Water hyacinth

Question 3.

Aestivation Heat absorption
Echolocation Fall in body temperature
Hibernation Ultrasonic sounds
patagium low metabolism

Answer:

Aestivation low metabolism
Echolocation Ultrasonic sounds
Hibernation Fall in body temperature
patagium Heat absorption

Question 4.

Secondary Treatment Disinfection
Grey water Floatation
Primary Treatment Reusuable waste water
Tertiary Treatment Sedimentation

Answer:

Secondary Treatment Sedimentation
Grey water Reusable waste water
Primary Treatment Floatation
Tertiary Treatment Disinfection

IV. Say true or false. Correct the false statements :

1. Sublimation is conversion of solid into liquid.
Answer:
False.
Correct statement: Sublimation is conversion of solid into Gas.

2. Nitrogen is an essential component of protein, DNA and chlorophyll.
Answer:
True.

Samacheer Kalvi 9th Science Guide Chapter 11 Atomic Structure

3. Plant proteins are excreted in theTorm of urea, uric acid or ammonia.
Answer:
False.
Correct statement : Animal proteins are excreted in the form of urea, uric acid or ammonia %

4. During respiration, plants and animals release carbon into the atmosphere in the form of carbon monoxide.
Answer:
False.
Correct statement : During respiration, plants and animals release carbon into the atmosphere in the form of Carbon dioxide

5. Bats are not blind.
Answer:
True.

Samacheer Kalvi 9th Science Guide Chapter 11 Atomic Structure

6. Earthworm come out of their burrow during summer season.
Answer:
False.
Correct statement: Earthworm come out of their burrow during rainy season.

7. Earthworm reacts positively to brighter light.
Answer:
False.
Correct statement: Earthworm reacts negatively to brighter light.

8. Clean and Fresh water is essential for every human activity.
Answer:
True.

9. Nicobar island is one of the biodiversity hotspots in India.
Answer:
True.

Samacheer Kalvi 9th Science Guide Chapter 11 Atomic Structure

V. Assertion and Reason type questions :

Mark the correct choice as :
(a) If both Assertion and Reason are true and Reason is the correct explanation of Assertion.
(b) If both assertion and reason are true but reason is not the correct explanation of assertion.
(c) If assertion is true but reason is false.
(d) If assertion is false but reason is true.

Question 1.
Assertion (A) : Biosphere is a dynamic and stable system.
Reason (R) : There is a constant interaction between biotic and abiotic components in the biosphere.
Answer:
(a) Both Assertion and Reason are true and Reason is the correct explanation of Assertion

Question 2.
Assertion (A) : Infiltration and Percolation are two related but different processes.
Reason (R) : They describe the movement of water through atmosphere.
Answer:
(c) Assertion is true but reason is false
Reason (R): They describe the movement of water through Soil.

Question 3.
Assertion (A) : Plants and animals can utilize atmospheric nitrogen.
Reason (R) : Atmosphere is a rich source of nitrogen.
Answer:
(d) Assertion is false but reason is true
Assertion (A) : Plants and animals cannot utilise atmospheric nitrogen.

Samacheer Kalvi 9th Science Guide Chapter 11 Atomic Structure

Question 4.
Assertion (A) : By increasing the amount of carbon dioxide, earth becomes warmer.
Reason (R) : Carbon dioxide is a green house gas.
Answer:
(a) Both Assertion and Reason are true and Reason is the correct explanation of Assertion

Question 5.
Assertion (A) : The moist skin in earthworm helps in oxygenation of blood.
Reason (R) : The slippery skin of earthworm is kept moist.
Answer:
(b) Both assertion and reason are true but reason is not the correct explanation of assertion
Reason (R) : The slippery skin of earthworm is kept moist as it respires through the skin. Moist skin helps in oxygenation of blood.

Samacheer Kalvi 9th Science Guide Chapter 11 Atomic Structure

VI. Very Short Answer Questions

Question 1.
Name three Biogeochemical cycles.
Answer:
Some of the important Biogeochemical cycles are :

  1. Water cycle
  2. Nitrogen cycle
  3. Carbon cycle.

Question 2.
List the forms of Precipitation.
Answer:
Precipitation includes

  • Drizzle
  • Rain
  • Snow
  • Hail.

Samacheer Kalvi 9th Science Guide Chapter 11 Atomic Structure

Question 3.
Mention the excretory forms of Animal proteins.
Answer:

  • Urea
  • Uric acid
  • Ammonia

Question 4.
What are the effects of carbon dioxide in the atmosphere?
Answer:

  • Green house effect
  • Global warming.

Question 5.
How are plants classified on the basis of water availability?
Answer:
On the Basis of water availability, plants have been classified as:

  • Hydrophytes
  • Xerophytes
  • Mesophytes.

Samacheer Kalvi 9th Science Guide Chapter 11 Atomic Structure

Question 6.
How are bats important to humans?
Answer:

  • Bats reduce insect population.
  • They help to pollinate plants.

Question 7.
What is the Ideal temperature range of earthworm?
Answer:
The Ideal temperatures range is 60-80°F.

VII. Answer briefly :

Question 1.
Define : Environmental Science.
Answer:
Environmental science is defined as the study of patterns, processes in the natural world and their modifications by human activities.

Samacheer Kalvi 9th Science Guide Chapter 11 Atomic Structure

Question 2.
What is biogeochemical cycle?
Answer:
The cyclic flow of nutrients between non-living and living factors of the environment are termed as Biogeochemical cycles.

Question 3.
How are clouds and fogs formed?
Answer:

  • At higher altitudes, the temperature is low. The water vapour present there condenses to form very tiny particles of water droplets.
  • These particles come close together to form clouds and fog.

Question 4.
How is carbon dioxide returned to atmosphere? :
Answer:
Carbon dioxide is returned to the atmosphere through

  • decomposition of dead organic matter,
  • burning fossil fuels
  • volcanic activities.

Samacheer Kalvi 9th Science Guide Chapter 11 Atomic Structure

Question 5.
Explain briefly the role of earth-worm in soil atmosphere, (or) soil health?
Answer:

  • Earthworm facilitates aeration, water infiltration.
  • It produces organic matter to increase crop growth.

Question 6.
What is worm castings? How is it useful?
Answer:

  • The faecal wastes of earthworm are called worm castings.
  • They are rich in nitrogenous content which adds fertility to the soil.

Question 7.
Point out the importance of water conservation.
Answer:

  • Water conservation creates more efficient use of the water resources.
  • It ensures enough usable water.
  • It helps to decrease water pollution.
  • It helps in increasing energy saving.

Samacheer Kalvi 9th Science Guide Chapter 11 Atomic Structure

Question 8.
According to you, which process of water cycle is adversely affected by human activities?
Answer:
Transpiration by which plants release water vapour through small pores in leaves and stems.
Reason : Human activities such as Deforestation, urbanisation.

Question 9.
Identify the given plant. How does it adapt itself to its habitat?
Samacheer Kalvi 9th Science Guide Chapter 24 Environmental Science-3
Answer:
Hydrilla:

  • Poorly developed Root.
  • Narrow (or) finely divided submerged leaves.

Samacheer Kalvi 9th Science Guide Chapter 11 Atomic Structure

Question 10.
What is grey water? %
Answer:
Grey water is reusable waste water from residential, commercial and industrial bathroom sinks, bath tub, shower drains and washing of clothes.

VIII. Answer in detail :

Question 1.
Draw a neat flow chart of Nitrogen cycle. Briefly explain the various processes involved in nitrogen cycle.
Answer:
Samacheer Kalvi 9th Science Guide Chapter 24 Environmental Science-4
Process involved in nitrogen cycle are explained below :

1. Nitrogen Fixation:
Process : Conversion of atmospheric Nitrogen (inert) into reactive compounds.
Agents : Bacteria and Bluegreen algae (cyanobacteria), (microorganism), Rhizobium.
Occurrence : Root nodules of leguminous plants peas, beans, etc.

2. Nitrogen Assimilation:
Process : Plants absorb nitrate ions and made into organic matter like proteins and nucleic acids.
Agents : Plants, animals.

3. Ammonification :
Process: Decomposition of nitrogenous waste into ammonium compounds.
Micro organism : Putrefying Bacteria, and fungi.
End Products : Urea, Uric acid (or) Ammonia.

4. Nitrification
Process: Ammonium compounds are oxidised to soluble nitrates.
Bacteria : Nitrification is caused by nitrifying bacteria.

5. Denitrification:
Process: Reduction of nitrate ions of soil into gaseous nitrogen which enters into the atmosphere.
Bacteria : Pseudomonas sp.

Samacheer Kalvi 9th Science Guide Chapter 11 Atomic Structure

Question 2.
Write the adaptations of mesophytes.
Answer:

  • The roots of mesophytes are well developed with root caps.
  • They have straight as well as branched stems.
  • Broad and thin leaves with waxy cuticles.
  • Waxy cuticles traps the moisture and lessens water loss.
  • Leaves have stomata which close in extreme heat and wind to prevent transpiration.

Samacheer Kalvi 9th Science Guide Chapter 11 Atomic Structure

Question 3.
Discuss the adaptations of earthworm with its applications.
Answer:
adaption : of Earthworm :
1. Stream-lined body:
Adaptation : Earthworm has cylindrical, elongated and segmented body.
Application : 1. To live in burrows, 2. Easy penetration into soil.

2. Skin: .
Adaptation : Mucus covers skin, 2. slippery moist skin.
Application : 1. It does not allow soil particle to stick on the skin.
2. Respiration through skin and oxygenation of blood.

3. Burrowing:
Adaptation : 1. Circular and longitudinal muscles in body.
2. Each segment of the lower surface of the body has number of bristles called setae.
Application: 1. Movement and subsoil burrowing.
2. To move through the soil and provide anchor in the burrows.

4. Aestivation
Adaptation : 1. During dry (or) hot condition, Earthworms moves deep into the soil and become inactive.
2. It secrets mucus and lowers metabolic rate.
Application: To reduce water loss.

5. Nocturnality:
Adaptation : Earthworm sense light through light-sensitive cells in the skin.
Remains in burrow during day.
Application : To detect light and changes in light intensity.

Samacheer Kalvi 9th Science Guide Chapter 11 Atomic Structure

Question 4.
Describe layout of a Farm pond.
Answer:
1. Farm pond is a dugout structure with definite shape and size.
2. They have proper inlet and outlet structures for collecting the surface run off flowing from the farm area.
3. The size and depth of the pond depend upon

  • The amount of land available.
  • The type of soil
  • Water requirement of farmers
  • The cost of excavation

4. The stored water is used forinigation.

Question 5.
What are all the strategies used to support water conservation?
Answer:
Water conservation strategies

  • Rain water harvesting.
  • Improved Irrigation techniques.
  • Use of traditional water harvesting structures.
  • Minimising domestic water consumption.
  • Awareness on water conservation.
  • Construction of farm ponds.
  • Recycling of water.

Samacheer Kalvi 9th Science Guide Chapter 11 Atomic Structure

Question 6.
List out any five advantages of Farm ponds.
Answer:
The advantages of farm ponds are-

  • They provide water to growing crops, without waiting for rainfall.
  • They reduce soil erosion.
  • They recharge ground water.
  • They improve drainage.
  • The excavated soil can be used to enrich soil in fields and levelling lands.
  • They promote fish rearing.
  • They provide water for domestic purposes and livestock.