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 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 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 20 Organ Systems in Animals

Tamilnadu State Board New Syllabus Samacheer Kalvi 9th Science Guide Pdf Chapter 20 Organ Systems in Animals Text Book Back Questions and Answers, Notes.

Tamilnadu Samacheer Kalvi 9th Science Solutions Chapter 20 Organ Systems in Animals

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 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.

Samacheer Kalvi 9th Science Guide Chapter 23 Economic Biology

Tamilnadu State Board New Syllabus Samacheer Kalvi 9th Science Guide Pdf Chapter 23 Economic Biology Text Book Back Questions and Answers, Notes.

Tamilnadu Samacheer Kalvi 9th Science Solutions Chapter 23 Economic Biology

9th Science Guide Economic Biology Text Book Back Questions and Answers

Samacheer Kalvi 9th Science Guide Chapter 23 Economic Biology

I. Choose the correct answer :

Question 1.
The production and management of fish is called
(a) Pisciculture
(b) Sericulture
(c) Aquaculture
(d) Monoculture
Answer:
(a) Pisciculture

Question 2.
Which one of the following is not an exotic breed of cow?
(a) Jersey
(b) Holstein-Friesan
(c) Sahiwal
(d) Brown Swiss
Answer:
(c) Sahiwal

Samacheer Kalvi 9th Science Guide Chapter 23 Economic Biology

Question 3.
Which one of the following is an Italian species of honey bee?
(a) Apis mellifera
(b) Apis dorsata
(c) Apis florae
(d) Apis cerana
Answer:
(a) Apis mellifera

Question 4.
Which one of the following is not an Indian major carp?
(a) Rohu
(b) Catla
(c) Mrigal
(d) Singhara
Answer:
(d) Singhara

Samacheer Kalvi 9th Science Guide Chapter 23 Economic Biology

Question 5.
Drones in the honey bee colony are formed from
(a) unfertilized egg
(b) fertilized egg
(c) parthenogenesis
(d) both b and c
Answer:
(a) unfertilized egg

Question 6.
Which of the following is an high milk yielding variety of cow?
(a) Holstein-Friesan
(b) Dorset
(c) Sahiwal
(d) Red Sindhi
Answer:
(a) Holstein-Friesan

Samacheer Kalvi 9th Science Guide Chapter 23 Economic Biology

Question 7.
Which Indian variety of honeybee is commonly used for apiculture?
(a) Apis dorsata
(b) Apis florea
(c) Apis niellifera
(d) Apisindica
Answer:
(d) Apis indica

Question 8.
…………….. is the method of grafting plants without soil.
(a) Horticulture
(b) Hydroponics
(c) Pomology
(d) None of these
Answer:
(b) Hydroponics

Question 9.
The symbiotic association of fungi and vascular plants is
(a) Lichen
(b) Rhizobium
(c) Mycorrhizae
(d) Azotobacter
Answer:
(c) Mycorrhizae

Samacheer Kalvi 9th Science Guide Chapter 23 Economic Biology

Question 10.
The plant body of mushroom is
(a) Spawn
(b) Mycelium
(c) Leaf
(d) All of these
Answer:
(b) Mycelium

II. Fill in the blanks :

1. Quinine drug is obtained from …………………
Answer:
Cinchona (cinjona maram)

2. Carica papaya leaf can cure disease.
Answer:
Dengue

3. Vermicompost is a type of soil made by …………… and microorganisms.
Answer:
Earthworm

Samacheer Kalvi 9th Science Guide Chapter 23 Economic Biology

4. …………… refers to the culture of prawns, pearl and edible oysters.
Answer:
Aquaculture

5. The largest member in a honey bee hive is is the ……………
Answer:
Queen Bee

6. …………… is a preservative in honey.
Answer:
Formic acid

7. …………… is the method of culturing different variety of fish in a water body.
Answer:
Polyculture

III. Say true or false. If false, correct Hie statement:

1. Mycorrhiza is an algae.
Answer:
Correct statement: Mycorrhiza is a tumgi

2. Milch animals are used in agriculture and transport.
Answer:
False
Correct statement: Milch animals are used in milk production

Samacheer Kalvi 9th Science Guide Chapter 23 Economic Biology

3. Apis florea is a rock bee.
Answer:
False
Correct statement: Apis florea is a rock bee.

4. Ongole is an exotic breed of cattle.
Answer:
False.
Correct statement: Ongole is an Indian breed of cattle.

5. Sheep manure contains high nutrients than farm yard manure.
Answer:
True.

IV. Differentiate the following :

(a) Exotic breed and Indigenous breed.
Answer:

Exotic Breed Indigenous Breed
The exotic breeds are imported from foreign countries. Indigenous Breeds are native of India.
They include Jersey, Brown Swiss, Holstein – Friesian. They include Sahiwal, Red Sindhi, Deoni and Gir.

Samacheer Kalvi 9th Science Guide Chapter 23 Economic Biology

(b) Pollen and Nectar
Answer:

Pollen Nectar
It is fine powder of microscopic particles from the male flower. It is a‘sweet sdbstance, produced by plants to attract pollinators such as bee, butterfly.
Pollen is produced by anther, male reproductive organ. Nectar is converted into Honey.

(c) Shrimp and Prawn
Answer:

Shrimp Prawn
Marine inhibited prawns are called Shrimps, which breed in deep sea. Prawn are crustaceans inhibited in fresh water, marine water, estuaries, etc

(d) Farmyard manure and Sheep manure
Answer:

Farmyard manure Sheep manure
It is a mixture of cattle dung, urine, litter material, and other dairy wastes. This is the manure of sheep or Goat
0.5% Nitrogen, 0.2% Phosphate, 0.5% potash. 3% Nitrogen, 1% phosphorus pentoxide 2% potassium oxide.
Less compared to sheep manure High nutrients.

V. Match the following :

Column A Column B
1. Lobsters Marine fish
2. Catla Pearl
3. Sea bass Shell fish
4. Oysters Paddy
5. Pokkali Fin fish
6. Pleurotus sps Psoriosis
7. Sarpagandha Oyster mushroom
8. Olericulture Reserpine
9. Wrighta tinctoria Vegetable farming

Answer:

Column A Column B
1. Lobsters Shell fish
2. Catla Fin fish Pearl
3. Sea bass Marine fish
4. Oysters Pearl
5. Pokkali Paddy
6. Pleurotus sps Oyster mushroom
7. Sarpagandha Reserpine
8. Olericulture Vegetable farming
9. Wrighta tinctoria Psoriosis

Samacheer Kalvi 9th Science Guide Chapter 23 Economic Biology

VI. Answer briefly :

Question 1.
What are the secondary metabolites?
Answer:
Most medicines are obtained either directly or indirectly from plants. All the major system of medicines such as Ayurveda, Yoga, Unani, Siddha, Homeopathy (AYUSH) use drugs obtained from plants and animals. These drugs from medicinal plants are called secondary metabolites.

Question 2.
What are the types of vegetable gardens?
Answer:
Types of vegetable gardens are

  1. Kitchen or Nutrition gardening
  2. Commercial gardening
  3. Vegetable forcing
  4. Greenhouse (or) Poly House
  5. Organic Vegetable Gardening.

Samacheer Kalvi 9th Science Guide Chapter 23 Economic Biology

Question 3.
Mention any two mushroom preservation methods.
Answer:
Drying and Vacuum Cooling are some methods used to preserve mushrooms.

Question 4.
Enumerate the advantages of vermicompost over chemical fertilizer.
Answer:

  • Vermicompost is free from pathogens and toxic elements.
  • It enhances the decomposition of organic matter in soil.
  • It is rich in beneficial microflora.
  • It contains valuable vitamins, enzymes and growth regulator substances.

Question 5.
What are the species of earthworm used for vermiculture?
Answer:
Among the vast community of earthworms, only very few species can be used for vermicompost production. They are Perionyx excavatus (Indian blue worm), Eisenia fetida (Red worms), Eudrilus eugeniae (African nightcrawler).

Samacheer Kalvi 9th Science Guide Chapter 23 Economic Biology

Question 6.
List the medicinal importance, of honey.
Answer:

  • Honey has an antiseptic and antibacterial property.
  • It is a blood purifier.
  • It helps in building up hemoglobin content in the blood.
  • It prevents cough, cold, fever, and relieves sore throat.
  • It is a remedy for ulcers of the tongue, stomach, and intestine.
  • It enhances digestion and appetite.

VII. Answer in detail :

Question 1.
Enumerate the advantage of hydroponics.
Answer:
Hydroponics was demonstrated by a German Botanist Julius Von Sachs in 1980.
Advantages:

  • Crops can be grown in places where the land is limited, doesn’t exist, or is heavily contaminated.
  • The climate – temperature, humidity, light intensification, the composition of the air can be monitored.
  • Conservation of water and nutrients.
  • Controlled plant growth.
  • No intrusion by weeds.
  • Fewer pests & diseases
  • Minimal use of insecticide or herbicides
  • In deserts and Arctic regions hydroponics can be an effective alternative method.
  • Hydroponics is successfully employed for the commercial production of seedless cucumber and tomato.

Question 2.
Define Mushroom culture. Explain the mushroom cultivation methods.
Answer:
Mushroom is a fungus belonging to basidiomycetes. It is rich in proteins, fibres, vitamins and minerals. Mushroom culture is the process of producing food, medicine, and other products by the cultivation of mushrooms.
Mushrooms can be cultivated either on paddy straw or on the wood log.
Major stages of mushroom cultivation are;

  • Composting: Compost is prepared by mixing paddy straw with a number of organic materials like cow dung and inorganic fertilizers. It is kept at about 50°C for one week.
  • Spawning: Spawn is the mushroom seed. It is prepared by growing fungal mycelium in grains under sterile conditions. Spawn is sown on the compost.
  • Casing: Compost is covered with a thin layer of soil. It gives support to the growing mushroom, provides humidity, and helps regulate the temperature.
  • Pinning: Mycelium starts to form a little bud, which will develop into mushrooms. Those little white buds are called pins.
  • Harvesting: Mushroom grows better in 15°C – 23°C. They grow 3 cm in a week which is the normal size for harvesting. In the third week, the first flush mushroom can be harvested.

Samacheer Kalvi 9th Science Guide Chapter 23 Economic Biology

Question 3.
What are the sources of organic resources for vermicomposting?
Answer:
Biologically degradable organic wastes are used as potential organic resources for vermicomposting.
They are :

  • Agricultural wastes (Crop residue, Vegetable waste, Sugarcane trash).
  • Crop residues (rice straw, tea wastes, cereal and pulse residues, rice husk, tobacco wastes, coir wastes).
  • Leaf litter.
  • Fruit and vegetable wastes.
  • Animal wastes (cattle dung, poultry droppings, pig slurry, goat and sheep droppings).
  • Biogas slurry.

Question 4.
Give an account of different types of fish ponds used for rearing fishes.
Answer:
Types of ponds for fish culture
The fish farm requires different types of the pond for the various developmental stages of fish growth. They are:

  1. Breeding pond: Healthy and sexually mature male and female fishes are collected and introduced in this pond for breeding. The eggs released by the female are fertilized by the sperm and fertilized eggs float in water as frothy mass.
  2. Hatchling pits: The fertilized eggs are transferred to hatching pits for hatching. Two types of hatching pits are hatcheries and hatching hapas.
  3. Nursery ponds: The hatchlings are transferred from hatching pits after 2 to 7 days. The hatchlings grow into fry and are cultured in these ponds for about 60 days with proper feeding till they reach 2 -2.5 cm in length.
  4. Rearing ponds: Rearing ponds are used to culture the fry. The fish fry are transferred from nursery pond to rearing ponds and are maintained for about three months till they reach 10 to 15 cm in length. In these rearing ponds the fry develops into fingerlings.
  5. Stocking pond: The stocking pond is also called a culture pond or production pond. These ponds are used to rear fingerlings upto the marketable size. Before releasing the fingerlings, the pond is manured with organic manure and inorganic fertilizers.

Samacheer Kalvi 9th Science Guide Chapter 23 Economic Biology

Question 5.
Classify the different breeds of the cattle with suitable examples.
Answer:
Samacheer Kalvi 9th Science Guide Chapter 23 Economic Biology-1

VIII. Higher Order Thinking Skills :

Question 1.
Biomanuring plays an important role in agriculture. Justify.
Answer:

  • Biomanuring reduces soil pollution, water pollution and air pollution, etc.
  • It protects soil health and promotes soil fertility.
  • It provides healthy production of vegetables, fruits etc.
  • It makes the soil fertile by adding nutrients like nitrogen.

Question 2.
Each bee hive consists of hexagonal cells. Name the material in which the cell is formed and mention the significance of the hexagonal cells.
Answer:

  • The comb of the bees is formed mainly by the secretion of the wax glands present in the abdomen of the worker bee.
  • A comb is a vertical sheet of wax with double layer of hexagonal / cells.
  • Hexagonal cells serve as storage vessels for honey as well as homes to raise the young bees.

Samacheer Kalvi 9th Science Guide Chapter 23 Economic Biology

9th Science Guide Economic Biology Additional Important Questions and Answers

I. Choose the correct answer :

Question 1.
Olericulture refers to the farming of ………………..
(a) Vegetable
(b) Flowers
(c) Fruits
(d) All of these
Answer:
a) Vegetable

Question 2.
India is the ………………..largest producer of vegetables next to China.
(a) First
(b) Second
(c) Third
(d) Fourth
Answer:
(b) Second

Samacheer Kalvi 9th Science Guide Chapter 23 Economic Biology

Question 3.
Tuber rose is cultivated from ………………..
(a) Madurai zone
(b) Hill area zone
(c) Coimbatore zone
(d) Hosurzone
Answer:
(c) Coimbatore zone

Question 4.
Green manure also helps in reclamation of ……………….. soils.
(a) Acidic
(b) Alkaline
(c) neutral
(d) None of these
Answer:
(b) Alkaline

Samacheer Kalvi 9th Science Guide Chapter 23 Economic Biology

Question 5.
Azolla having a cyanobacterial symbiotic association with ………………..
(a) Azotobacter
(b) Azospirillum
(c) Mycorrhizae
(d) Anabaena
Answer:
(d) Anabaena

Question 6.
Quinine is a best drug for treatment of ………………..
(a) Dengue
(b) Psoriasis
(c) Malaria
(d) Leukemia
Answer:
(c) Malaria

Question 7.
Nilavembu kashayam is givep to patients/people to protect from . ………………..
(a) Dengue
(b) Chikungunya
(c) Diabetes
(d) All of these
Ans :
(d) All of these

Samacheer Kalvi 9th Science Guide Chapter 23 Economic Biology

Question 8.
Reserpine is derived from ………………
(a) Cathyranthusroseus
(b) Rauwolfia serpentina
(c) Hemidesmus indicus
(d) Aloe vera
Answer:
(b) Rauwolfia serpentina

Question 9.
Casing is done on the mushroom to ………………..
(a) support the growth of mushroom
(b) provide humidity to mushroom
(c) regulate the temperature
(d) All the above
Answer:
(d) All the above

Question 10.
The growth medium of Aeroponics is
(a) Nutrients
(b) Water
(c) air
(d) soil
Answer:
(c) air

Samacheer Kalvi 9th Science Guide Chapter 23 Economic Biology

Question 11.
The Indigenous Draught breed from Thanjavur district is ………………..
(a) Pulikulam
(b) Bargur
(c) Ongole
(d) Umblachery
Answer:
(d) Umblachery

Question 12.
………………..are low in fibre and contain a high level of carbohydrates, protein, and other
nutrients.
(a) Silage
(b) Concentrates
(c) Roughage
(d) None of these
Answer:
(b) Concentrates

Samacheer Kalvi 9th Science Guide Chapter 23 Economic Biology

Question 13.
Operation Flood is the programme for ………………..development.
(a) Dairy
(b) Cattle
(c) Marine
(d) Agriculture
Answer:
(a) Dairy

Question 14.
Air-breathing fishes are cultured in ………. water.
(a) Brackish
(b) Fresh
(c) Marine
(d) All of these
Answer:
(b) Fresh

Question 15.
Central Marine Fisheries Research Institute (CMFRI) is situated at …………………
(a) Chennai
(b) Mumbai
(c) Cochin
(d) Vizag
Answer:
(c) Cochin

Samacheer Kalvi 9th Science Guide Chapter 23 Economic Biology

Question 16.
Culture of fishes along with Agricultural crops is known as ………………..
(a) Polyculture
(b) Extensive culture
(c) Integrated culture
(d) Intensive culture
Answer:
(c) Integrated culture

Question 17.
The longest marine water prawn is
(a) Penaeus Indicus
(b) Penaeus monodon
(c) Macro brachium rosenbergii
(d) Macro brachium malcoumsonii
Answer:
(b) Penaeus monodon

Samacheer Kalvi 9th Science Guide Chapter 23 Economic Biology

Question 18.
Earthworms are sacred – This statement was made by ………………..
(a) Aristotle
(b) Darwin
(c) Plato
(d) Cleopatra
Answer:
(d) Cleopatra

Question 19.
Vermicompost is similar to ……………….. in colour and appearance.
(a) sheep manure
(b) Farmyard manure
(c) Green manure
(d) All of these
Answer:
(b) Farmyard manure

Question 20.
………………..is an enzyme present in Honey
(a) Sucrose
(b) Dextrose
(c) Invertase
(d) Maltase
Answer:
(c) Invertase

Samacheer Kalvi 9th Science Guide Chapter 23 Economic Biology

Question 21.
Fastest growing sector in Agriculture is ………………..
(a) Vegetable forcing
(b) Hydroponics
(c) Greenhouse
(d) Aqua ponies
Answer:
(c) Greenhouse

Question 22.
Which of the following are Indian cattle?
(i) Bos indicus
(ii) Bos domesticus
(iii) Bos bubalis
(iv) Bos vulgaris
(a) (i) and (ii)
(b) (i) and (iii)
(c) (ii) and (iii)
(d) (iii) and (iv)
Answer:
(b) (i) and (iii)

Samacheer Kalvi 9th Science Guide Chapter 23 Economic Biology

Question 23.
Which one of the following is referred as red worms?
(a) Eudrilus fetida
(b) Eudrilus eugieniae
(c) Eisenia fetida
(d) Lampito mauritii
Answer:
(c) Eisenia fetida

Question 24.
Mehsana is a breed of
(a) Cow
(b) Buffalo
(c) Goat
(d) Sheep
Answer:
(b) Buffalo

Samacheer Kalvi 9th Science Guide Chapter 23 Economic Biology

Question 25.
Binomial name of Nilavemubu is ………………..
(a) Leucas Aspera
(b) Andrographis paniculata
(c) Crotalaria juncea
(d) Cassia fistula
Answer:
(b) Andrographis paniculata

II. Fill in the blanks:

1. ………….. is the most intensive type of vegetable growing.
Answer:
Vegetable forcing

2. India stands first in the world in the production of…………………… and …………………….
Answer:
Potato, Lady’s finger

Samacheer Kalvi 9th Science Guide Chapter 23 Economic Biology

3. Compost is a …………………… as well as a fertilizer, which is rich in nutrients.
Answer:
Soil conditioner

4. Earthworms eat …………………… and excrete it in a digested form.
Answer:
biomass

5. Green manure is obtained from undecomposed green material derived from …………………… plants.
Answer:
Leguminous

6. …………………… is a type of Bio-fertilizers that are capable of producing antifungal and antibacterial compounds.
Answer:
Azotobacter

Samacheer Kalvi 9th Science Guide Chapter 23 Economic Biology

7. Mycorrhizae increase the uptake of …………………….
Answer:
Phosphorous

8. …………………… is the study of chemical substances derived from plants .
Answer:
Phytochemistry

9. …………………… is used as an antidote for snake bite.
Answer:
Chivan Amalpodi (Sarpagandha)

Samacheer Kalvi 9th Science Guide Chapter 23 Economic Biology

10. Alkaloids, Terpenoids, flavonoids etc are called …………………… metabolites.
Answer:
Secondary

11. India’s first anti-diabetic ayurvedic drug is …………………….
Answer:
BGR-34

12. Mushroom is a fungi belonging to …………………….
Answer:
Basidiomycetes

Samacheer Kalvi 9th Science Guide Chapter 23 Economic Biology

13. Hydroponics was first demonstrated by German botanist …………………….
Answer:
Julius Von Sachs

14. Milk production in cattle depends upon the duration of ……………………
Answer:
Lactation

15. Jallikattu madu belongs to …………………… breed.
Answer:
Indigenous Draught

16. Young female calf is called as……………………
Answer:
Heifer

Samacheer Kalvi 9th Science Guide Chapter 23 Economic Biology

17. Dr.Verghese Kurien is the Father of …………………….
Answer:
White revolution

18. Panchagavya is an…………………… Fertilizer .
Answer:
organic liquid

19. The Central Institute of Brackish Water Aquaculture (CIBA) was established in …………………….
Answer:
1987

20. India holds …………………… position in Marine fish production in the world.
Answer:
10th

Samacheer Kalvi 9th Science Guide Chapter 23 Economic Biology

21. The eggs released by the female fish are fertilized by the sperm and fertilized eggs float in water as …………………….
Answer:
frothy mass

22. Hatching period in Hatchling pits is …………………….
Answer:
2-7days

Samacheer Kalvi 9th Science Guide Chapter 23 Economic Biology

23. PUFA stands for ……………………
Answer:
Poly Unsaturated Fatty Acid

24. ………………….. culture is the oldest and traditional method of prawn culture practiced in Kerala.
Answer:
Pokkali

25. The nutrient rich materials that are excreted by earthworms knows as …………………….
Answer:
worm castings

26. The …………………… cells contain honey and pollen.
Answer:
Storage

Samacheer Kalvi 9th Science Guide Chapter 23 Economic Biology

27. …………………… and…………………… give sweet taste to the honey.
Answer:
Dextrose, Sucrose

28. One kilogram of honey contains …………………… calories.
Answer:
3200

29. …………………… is widely used in cosmetic and pharmaceutical industries.
Answer:
Bee wax

Samacheer Kalvi 9th Science Guide Chapter 23 Economic Biology

30. …………………… is a nodulating type of microorganism associating symbiotically with the root of legume plants.
Answer:
Rhizobium

31. …………………… is the maintenance of bee colonies in modem hives.
Answer:
Beekeeping

III. Match the following:

I.

(1) Homeopathy a) Hippocrates
(2) Siddha b) Patanjali
(3) Unani c) Charaka Samhita
(4) Ayurveda d) Agasthya
(5) Yoga e) Samuel Hahnemann

Answer:
1-e, 2-d,3 -a,4-c,5-b

Samacheer Kalvi 9th Science Guide Chapter 23 Economic Biology

II.

(1) Rhizobium a) Crop plants
(2) Azolla b) Antifungal and antibacterial compounds
(3) Azotobacter c) vascular plants
(4) Mycorrhizae d) leguminous plants
(5) Azospirillum e) Floating nitrogen factory

Answer:
1-d, 2-e, 3-b, 4-c, 5-a

III.

(1) Paddy straw Mushroom a) Volvariella volvacea
(2) Lingzhi Mushroom b) Agaricus bisporus
(3) Oyster Mushroom c) Pieurotussps
(4) Button Mushroom d) Ganoderma lucidum

Answer:
1-a, 2-d, 3-c, 4-b

Samacheer Kalvi 9th Science Guide Chapter 23 Economic Biology

IV.

(1) Bargur a) Indigenous dairy breeds
(2) Tharparkar b) Buffalo breeds
(3) Murrah c) Indigenous Draft breeds
(4) Gir d) Dual-purpose breeds

Answer:
1 – c, 2d, 3 – b, 4 – a

IV. Say true or false. If false, correct the statement:

1. Edible mushrooms are valuable source of supplementary lipids.
Answer:
False.
Correct statement: Edible mushrooms are valuable source of supplementary proteins.

2. The yield of greenhouse is very high compared to outdoor cultivation.
Answer:
True.

Samacheer Kalvi 9th Science Guide Chapter 23 Economic Biology

3. Rhizobium fix atmospheric nitrogen and convert them to nitrates.
Answer:
False.
Correct statement: Rhizobium fix atmospheric nitrogen and convert them to ammonia.

4. The roots in hydroponic plant absorb water and nutrients but do not perform the anchoring function.
Answer:
True.

5. Spawn is prepared by growing fungal mycelium in grains under fertile conditions.
Answer:
False.
Correct statement: Spawn is prepared by growing fungal mycelium in grains under sterile conditions.

6. Local breed animals show excellent resistance to diseases.
Answer:
True

Samacheer Kalvi 9th Science Guide Chapter 23 Economic Biology

7. Milk production of Buffaloes are less than that of cow.
Answer:
False.
Correct statement: Milk production of Buffaloes are more than that of cow.

8. The salinity of brackish water ranges from 30-35 ppt.
Answer:
False.
Correct statement: The salinity of brackish water ranges from 1-32 ppt.

9. Fish meal is used as a feed for cattle and poultry farming animals.
Answer:
True.

10. Earthworm feeds on inorganic wastes and excrete it in digested form known as castings.
Answer:
False.
Correct statement: Earthworm feeds organic wastes and excrete it in a digested form known as castings.

Samacheer Kalvi 9th Science Guide Chapter 23 Economic Biology

11. Medicinal plants contain compounds that can be used for therapeutic purposes.
Answer:
True.

12. Anthraquinones is obtained from Ocimum sanctum.
Answer:
False.
Correct statement: Anthraquinones is obtained from Aloevera.

13. Aquaponics is a technique of growing plants with their root supplied with moisture present in the air.
Answer:
False.
Correct statement: Aeroponics is a technique of growing plants with their root supplied with moisture present in the air.

Samacheer Kalvi 9th Science Guide Chapter 23 Economic Biology

V. Assertion and Reason :

(a) 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. If both Assertion and Reason are true and Reason is the correct explanation of Assertion.
b. If both Assertion and Reason are true that 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 : Apiculture, vermiculture are gaining more importance.
Reason : They have economical and commercial values.
Answer:
(a) Both Assertion and Reason are true and Reason is the correct explanation of Assertion

Samacheer Kalvi 9th Science Guide Chapter 23 Economic Biology

Question 2.
Assertion : Foreign dairy breeds are preferred over local breeds.
Reason: The foreign breeds have shorter lactation periods.
Answer:
(c) Assertion is true but Reason is false
Reason : The foreign breeds have longer lactation periods.

Question 3.
Assertion : Bullocks are good draft animals in draft breeds.
Reason : Cows are poor milk yielders in draft (or) Draught breeds.
Answer:
(b) Both Assertion and Reason are true that Reason is not the correct explanation of Assertion

Question 4.
Assertion : Porous soil permits both aeration and quick absorption of water.
Reason : The burrowing and soil feeding habits of earthworm make the soil
porous.
Answer:
(a) Both Assertion and Reason are true and Reason is the correct explanation of Assertion

Samacheer Kalvi 9th Science Guide Chapter 23 Economic Biology

Question 5.
Assertion : Hydroponics can be defined as a soilless growing system in which plants grow in water.
Reason : If a plant is provided with water, minerals and required nutrients, it will grow well and yield more even in the absence of soil.
Answer:
(a) Both Assertion and Reason are true and Reason is the correct explanation of Assertion

Question 6.
Assertion : Fish and other varieties of aquatic animals are used as food.
Reason : Fish and other varieties of sea food constitute good source of nutrition
Answer:
(a) Both Assertion and Reason are true and Reason is the correct explanation of Assertion

Question 7.
Assertion : The production of food from animal sources has increased greatly in the last few decades.
Reason : Operation flood and blue revolution production has increased in recent years.
Answer:
(b) Both Assertion and Reason are true and Reason is not the correct explanation of Assertion

Blue revolution is the concept of rapid increase in the production of fish and marine product.

Samacheer Kalvi 9th Science Guide Chapter 23 Economic Biology

VI. Define the following.

a. Pisciculture
Answer:
Pisciculture or Fish culture is the process of breeding and rearing of fishes in ponds, reservoirs (dams), lakes, rivers, and paddy fields.

b. Apiculture
Answer:
Apiculture is the rearing of honey bee for honey. It is called Beekeeping

Samacheer Kalvi 9th Science Guide Chapter 23 Economic Biology

c. Vermiculture
Answer:
Vermiculture involves the artificial rearing or cultivation of earthworms and using them for the production of compost from natural organic wastes.

d. Maricuiture (or) Marine water aquaculture
Answer:
The cultivation of aquatic organisms in seawater is referred as Mariculture (or) Sea farming.

e. Floriculture (or) Flower Farming
Answer:
Floriculture is the art of cultivation of flowering and ornamental plants in garden for beauty or floristry.

f. Compost
Answer:
Compost is a soil conditioner as well as a fertilizer, which is rich in nutrients.

Samacheer Kalvi 9th Science Guide Chapter 23 Economic Biology

g. Pomiculture
Answer:
Pomiculture is cultivation, development, entrancement of Fruits.

h. Pinning
Answer:
Pinning is the development of little white buds from mycelium.

VII. Very Short Answer questions :

Question 1.
Name the main classes of Horticulture.
Answer:
They are four main classes of Horticulture

  1. Pomology (fruit farming),
  2. Olericulture (vegetable farming),
  3. Floriculture (flowers farming),
  4. Landscape gardening.

Samacheer Kalvi 9th Science Guide Chapter 23 Economic Biology

Question 2.
What is Floriculture?
Answer:
Floriculture is the art of cultivation of flowering and ornamental plants in garden for beauty (or) floristry.

Question 3.
What is spawning?
Answer:
Spawn is the mushroom seed. It is prepared by growing fungal mycelium in grains under sterile conditions. Spawning is the sowing or planting of spawn on the compost.

Samacheer Kalvi 9th Science Guide Chapter 23 Economic Biology

Question 4.
What is Vermicompost?
Answer:
Vermicompost is a method of making compost with the use of earthworms, which ^ generally live in soil.

Question 5.
List the leguminous plants providing green manure.
Answer:

  • Sunhemp (Crotolariajuncea)
  • Dhaincha (Sesbania aculeata)
  • Sesbania (Sesbania speciosa)

Question 6.
Define: phytochemistry.
Answer:
Phytochemistry is the study of phytochemicals which are chemical substances derived from various parts of the plant.

Samacheer Kalvi 9th Science Guide Chapter 23 Economic Biology

Question 7.
Name any three edible mushrooms.
Answer:

  1. Button mushroom (Agaricus bisporus)
  2. Oyster mushroom (Pleurotus sps),
  3. Paddy straw mushroom (Volvariella volvacea).

Question 8.
Mention the main problems of harvesting mushrooms.
Answer:

  1. Discolouration
  2. Weight and flavour loss.

Samacheer Kalvi 9th Science Guide Chapter 23 Economic Biology

Question 9.
Name any three methods to increase mushroom life.
Answer:

  1. Freezing
  2. Vacuum Cooling
  3. Gamma radiation and storing at 15°C.

Question 10.
Write classification of cattle breeds.
Answer:
Cattle breeds are classified into three types:

  1. Dairy breeds
  2. Drought (or) Draft breeds
  3. Dual-purpose breeds.

Question 11.
How is the Fish Meal prepared?
Answer:
Fish meal is prepared from the wastes of fish oil (or) from whole fish.

Question 12.
List the methods employed in Prawn Culture,
Answer:

  1. Seed collection and hatchery method.
  2. Paddy cum prawn culture method.

Question 13.
What is Bee wax?
Answer:
Bee wax is the natural by-product secreted by the wax glands of worker bee to construct the combs of a beehive.

Samacheer Kalvi 9th Science Guide Chapter 23 Economic Biology

Question 14.
Mention the aim of operation Flood.
Answer:
Operation Flood is based on dairy commodity aid to increase milk supply in urban y areas.

Question 15.
What does NDDB stand for?
Answer:
NDDB – National Dairy Development Board.

VIII. Short Answer questions :

Question 1.
How is compost prepared?
Answer:
Compost is produced by the decomposition of organic matter such as crop residues,
animal wastes, food wastes, industrial and municipal wastes by microorganisms under controlled conditions.

Question 2.
Mention the advantages of Green Manure.
Answer:

  • Green Manure improves soil structure.
  • It increases water holding capacity and decreases soil loss by erosion.
  • It also helps in reclamation of alkaline soils and reduces weed proliferation.

Samacheer Kalvi 9th Science Guide Chapter 23 Economic Biology

Question 3.
Write short notes on Mushrooms;
Answer:

  • Mushroom is a fungi belonging to basidiomycetes.
  • It is rich in proteins, fibres, vitamins and minerals.
  • Cultivation of Mushroom takes one to three months.

Question 4.
Explain briefly about Aquaponics.
Answer:

  • Aquaponics is a system of a combination of conventional aquaculture with hydroponics in a symbiotic environment.
  • Two main parts are (i) Aquaculture – for raising aquatic animals like fish (ii) hydroponics – for raising plants.

Question 5.
Write short notes on Intensive Cattle Development Programme.
Answer:

  • Intensive Cattle Development Programme is based on cross-breeding of indigenous cows with exotic European breeds to increase milk production.
  • New methods and modem equipments are made available for machine – milking of cows.

Samacheer Kalvi 9th Science Guide Chapter 23 Economic Biology

Question 6.
Differentiate Extensive and Intensive Fish culture.
Answer:
Extensive Fish culture

  1. Culture of fishes in large areas.
  2. Low stocking density
  3. Natural feeding

Intensive Fish culture

  1. Culture of fishes in small areas.
  2. High stocking density
  3. Artificial feeding

Question 7.
What is green manure? How is it beneficial?
Answer:
Green manure is obtained by collection and decomposition of green leaves, twigs of trees, shrubs, and herbs growing in wastelands, field bunds etc. Green manure improves soil structure, increases water-holding capacity, and decreases soil loss by erosion. It also helps in the reclamation of alkaline soils and reduces weed proliferation. It is manure obtained from undecomposed green material derived from leguminous plants e.g. Sunhemp, Dhaincha, etc.

Samacheer Kalvi 9th Science Guide Chapter 23 Economic Biology

Question 8.
Enumerate the nutritional values of prawns.
Answer:

  • Prawns are a rich nutritive source of protein, vitamin A & D, Glycogen and Amino acids.
  • They contain less amount of fat.
  • Cultured prawns provide Poly Unsaturated Fatty Acid (PUFA).

Question 9.
List the important methods of vermicomposting.
Answer:

  • Bin or Container method.
  • Vermicomposting of organic wastes in field pits.
  • Vermicomposting of organic wastes on ground heaps.

Samacheer Kalvi 9th Science Guide Chapter 23 Economic Biology

Question 10.
What do you know about AYUSH?
Answer:

  • AYUSH is the ministry of Government of India for Indian (or) Alternative Medicine. ‘
  • AYUSH refers to Ayurveda, Yoga, Unani, Siddha and Homeopathy.

Question 11.
Why do we call Haryana and Kankrej breed of cattle as dual-purpose breeds?
Answer:
Haryana, Kankraj breeds

  • provide milk ,
  • also useful for farm work.
    So, they are called Dual-purpose breeds.

Question 12.
How is the division of labour observed in honey bees?
Answer:
Division of labour by Honey bees :
Queen Bee: Responsible for laying eggs in a colony.
Drones: They fertilize the eggs, produced by Queen Bee.
Worker Bee :
Functions

  • Collect Honey
  • Look after the young ones
  • Clean the comb
  • Defend the hive
  • Maintain the temperature of beehive.

Samacheer Kalvi 9th Science Guide Chapter 23 Economic Biology

Question 13.
What is the nutritional importance of fish liver oils? Name any two marine fishes which yield these oils.
Answer:
Nutritional Importance of Fish liver oil:

  • Great medicinal value
  • They are rich in Vitamin A, D, and E.

Two marine fishes: Shark, Tuna.

IX. Long Answer questions :

Question 1.
Compare types of Bio fertilisers with their functions.
Answer:
Samacheer Kalvi 9th Science Guide Chapter 23 Economic Biology-2
Samacheer Kalvi 9th Science Guide Chapter 23 Economic Biology-3

Samacheer Kalvi 9th Science Guide Chapter 23 Economic Biology

Question 2.
What are the types of honey bees found in a colony?
Answer:
There are three types of individuals in a colony namely the Queen bee, the drones and the worker bees.

  1. Queen Bee: The queen is the largest member and the fertile female of the colony. They are formed from fertile eggs. The queen is responsible for laying eggs in a colony. The life span of the queen bee is 3-4 years.
  2. Drones: They are fertile males. They develop from unfertilized eggs. They are larger than the workers and smaller than the queens. Their main function is to fertilize the eggs produced by the queen.
  3. Worker Bees: They are sterile female bees and are the smallest members of the colony. Their function is to collect honey, look after the young ones, clean the comb, defend the hive and maintain the temperature of the beehive.

Question 3.
Discuss various types of Honey bees with their functions.
Answer:
Samacheer Kalvi 9th Science Guide Chapter 23 Economic Biology-4

Samacheer Kalvi 9th Science Guide Chapter 23 Economic Biology

Question 4.
Explain the structure of Honey Bee Comb.
Answer:
The comb of the bees is formed mainly by the secretion of the wax glands present in the abdomen of the worker bee.
Comb : It is a vertical sheet of wax with double layer of hexagonal cells.

Types of Cells:
(i) Storage cell:

  • They are built in the margin and at the top of the comb.
  • It contains honey and pollen.

(ii) Brood cells : They are built in the centre and the lower part of the comb. They
are dividecf into three cells such as

  • Worker chamber
  • Drone chamber
  • Queen chamber

Where the larvae developing into worker, drone and queen aye reared.

Question 5.
How is honey formed?
Answer:

  • The honey bees suck the nectar from various flowers.
  • The nectar passes to the honey sac, where sucrose mixes with nectar.
  • By enzymatic action, Nector along with sucrose is converted into Honey.
  • Honey is stored in the special chambers of the hive.

Samacheer Kalvi 9th Science Guide Chapter 23 Economic Biology

Question 6.
Discuss the various nutrients present in Honey.
Answer:
Honey is a sweet viscous, edible natural food product. ‘

  • Sweet taste : Dextrose and sucrose give sweet taste to the honey.
  • Honey contains protein, free amino acids, vitamins like ascorbic acid etc.
  • Acids such as citric acid, gluconic acid and formic acid are found in honey.
  • Minerals such as calcium, Iron, Phosphorous and manganese are present.
  • Invertase is the enzyme present in honey.

Question 7.
Give an account on medicinal plants.
Answer:

(1) Katralai (Aloe vera)
It is herbal leaves.
The drug derived from it, is Anthraquinones.
This is best treatment for skin problems and cancer. It heal wounds.

(2) Tulsi (Octimum sanctum)
It is an important herb.
Leaves have medicinal value.

Uses :

  • Best medicine for cold and fever.
  • It is also useful for cardiac diseases, gynecological disorder.
  • Skin disorders and respiratory problems can also be treated.
    Sura’s o Science – 9th Std o Unit 23 o Economic Biology

(3) Nilavembu (Andrograhis paniculata)
It is a herbal plant with roots and leaves have medicinal values.
Uses :

  • It is the best tonic for dengue fever.
  • It is also used to treat diabetes and malaria.
  • It is best remedy for ulcer, Influenza, Chikungunya etc.,

(4) Vepalai (Neem) – (Wrightia tinctoria)
It is a medicinal plant with eVtry part has medicinal values.
Uses:

  • It has antipyretic, antibacterial and antitumour.
  • It gives best immunity power.
  • It is used to treat 4rin infections (or) diseases such as Psoriasis.
  • It is also good for respiratory disorders, diarrhoea and Swellings.

(5) Pappali (Carica papaya)
Like neem, every part of papaya has medicinal benefits.
Uses:

  • Best medicine for Dengue.
  • It reduces risk of heart diseases, diabetes arid cancer.
  • It lowers blood pressure and heals wounds.

Samacheer Kalvi 9th Science Guide Chapter 23 Economic Biology

Question 8.
What are biofertilisers? Give examples. Why are biofertilisers better than other fertilisers?
Answer:
Biofertilisers are substances that contain living microorganisms, when applied to plant promote growth by increasing primary nutrients to host plant.
Examples: (1) Rhizobium (2) Azospirillum (3) Azotobacter (4) Mycorrhizae (5) Azolla

Advantages of Biofertiser over chemical fertilisers :

  • Biofertilizers are environmental friendly fertilizers.
  • They enrich the nutrient quality of soil.
  • They sustain soil health.
  • They improve texture, structure and water-holding capacity of soil.
  • No adverse effect on plant growth and soil fertility.

Question 9.
Write short notes on
a) Importance of greenhouses
b) Uzahavan mobile Application
c) Major floriculture zones
d) Azospirillum
Answer:
(a) Importance of Greenhouses

  • Continuous production of disease-free plants.
  • Very less water requirement and less pesticide usage.
  • Very high yield and protection from uncertain weather.

(b) Uzhavan App:

  • Launched by the Government of Tamilnadu.
  • It provides information to farmers about subsidies, crop insurance, and stock of seeds and fertilizer.

(c) Major Floriculture zones :

  • Hosurzone
  • Chennai zone
  • Madurai zone
  • Trichy zone
  • Coimbatore zone
  • Kanyakumari zone
  • Hill area zone

(d) Azospirillum :

  •  It has the ability to use Atmospheric Nitrogen and transport to this nutrient crop plants
  •  It increases grain productivity, (e.g.) cereals 5-20%, millets 30% and Fodders 50%.

Samacheer Kalvi 9th Science Guide Chapter 23 Economic Biology

Question 10.
Explain the feeding management of dairy cattle.
Answer:

  1. Dairy cattle need balanced rations containing all nutrients in a proportional amount.
  2. Food additives should contain minerals, vitamins, antibiotics and hormones to
    promote the growth of animals, good yield of milk, and protect from diseases.
  3. The daily average feed ratio of milking cow is:
    • 15 – 25 kg of roughage (dry grass and green fodder)
    •  4 – 5 kg of green mixture.
    • 100- 150 litres of water.

X. Thinking Skills.

Question 1.
Arun and Akash were given fertilisers and earthworm compost both to be used in the fields. Akash preferred to use earthworm compost. Why did not select the fertilizers?
Answer:

  • Inorganic fertilizers pollute the soil.
  • Inorganic fertilizers contain chemicals that are toxic in nature and will result in health problems.

Samacheer Kalvi 9th Science Guide Chapter 23 Economic Biology

Question 2.
What is pasturage and how is it related to honey production?
Answer:

  • Pasturage is land with herbaceous vegetation cover used for unregulated livestock ; as a part of farms in arid regions.
  • Better pasturage provides better habitat for honey bee and honey production.

Samacheer Kalvi 9th Science Guide Chapter 15 Carbon and its Compounds

Tamilnadu State Board New Syllabus Samacheer Kalvi 9th Science Guide Pdf Chapter 15 Carbon and its Compounds Text Book Back Questions and Answers, Notes.

Samacheer Kalvi 9th Science Solutions Chapter 15 Carbon and its Compounds

9th Science Guide Carbon and its Compounds Text Book Back Questions and Answers

 Samacheer Kalvi 9th Science Guide Chapter 15 Carbon and its Compounds

I. Choose the correct answer :

Question 1.
A phenomenon in which an element exists in different modification in same physical state is called
(a) isomerism
(b) allotropy
(c) catenation
(d) crystallinity
Answer:
(b) allotropy

Question 2
Carbon forms large number of organic compounds due to
(a) Allotropy
(b) Isomerism
(c) Tetravalency
(d) Catenation
Answer:
(d) Catenation

 Samacheer Kalvi 9th Science Guide Chapter 15 Carbon and its Compounds

Question 3.
Nandhini brings her lunch every day to school in a plastic container which has resin code number 5. The container is made of
(a) Polystyrene
(b) PVC
(c) Polypropylene
(d) LDPE
Answer:
(c) Polypropylene

Question 4.
Plastics made of Polycarbonate (PC) and Acrylonitrile Butadiene Styrene (ABS) . are made of resin code …………………
(a) 2
(b) 5
(c) 6
(d) 7
Answer:
(a) 7

 Samacheer Kalvi 9th Science Guide Chapter 15 Carbon and its Compounds

Question 5.
Graphene is one atom thick layer of carbon obtained from
(a) diamond
(b) fiillerene
(c) graphite
(d) gas carbon
Answer:
(c) graphite

 Samacheer Kalvi 9th Science Guide Chapter 15 Carbon and its Compounds

Question 6.
The legal measures to prevent plastic pollution come under the Protection …………….. Act 1988.
(a) Forest
(b) Wildlife
(c) Environment
(d) Human rights
Answer:
(c) Environment

II. Fill in the blanks :

1. ………………. named carbon.
Answer:
Antoine Lavoisier

2. Buckminster Fullerene contains ………………… carbon atoms.
Answer:
60

3. Compounds with same molecular formula and different structural formula are known as ………………….. .
Answer:
Isomers

 Samacheer Kalvi 9th Science Guide Chapter 15 Carbon and its Compounds

4. …………….. is a suitable solven for Sulphur.
Answer:
Allotropy

5. There are ……………. plastic resin codes.
Answer:
seven

III. Match the following :

Alkyne Bucky Ball
Andre Geim Oxidation
C60 Graphene
Thermocol Triple bond
Combution Polystyrene

Answer:

Alkyne Triple bond
Andre Geim Graphene
C60 Bucky Ball
Thermocol Polystyrene
Combution Oxidation

 Samacheer Kalvi 9th Science Guide Chapter 15 Carbon and its Compounds

IV. Answer in briefly :

Question 1.
Differentiate graphite and diamond.
Answer:

Graphite Diamond
Each carbon atom has three covalent bonds. Each carbon atom has four covalent bonds.
Soft, slippery to touch and opaque Hard, heavy and transparent
It has planar layers of hexagon units. It has tetrahedral units linked in three dimension
It is conductor of heat and electricity. It is non-conductor of heat and electricity

Question 2.
Write all possible isomers of C4H10
Answer:
Samacheer Kalvi 9th Science Guide Chapter 15 Carbon and its Compounds 1

Question 3.
Carbon forms only covalent compounds. Why?
Answer:
Carbon forms only covalent compounds because it has 4 electrons, in its.

 Samacheer Kalvi 9th Science Guide Chapter 15 Carbon and its Compounds

Question 4.
Define Allotrophy.
Answer:
Allotrophy is a property by which are element can exist in more than one form that are physically different and chemically similar.

Samacheer Kalvi 9th Science Guide Chapter 15 Carbon and its Compounds 1

Question 5.
Why are one-time use and throwaway plastics harmful?
Answer:

  1. Use and throwaway plastics cause short and long-term environmental damage.
  2. Half of all the plastic made today is used for throwaway plastic items. These block drains and pollute water bodies.
  3. One-time use plastic causes health problems for humans, plants and animals.
  4. Some examples are plastic carry bags, cups, plates, straws, water pouches, cutlery and plastic sheets used for food wrapping.

 Samacheer Kalvi 9th Science Guide Chapter 15 Carbon and its Compounds

V. Answer in detail :

Question 1.
What is catenation? How does carbon form catenated compounds?
Answer:
Catenation is binding of an element to itself or with other elements through covalent bonds to form open chain or closed chain compounds.

  • Carbon is the most common element which undergoes catenation and long chain compounds.
  • Carbon atom links repeatedly to itself through covalent bond to form linear branched chain (or) ring structure

Samacheer Kalvi 9th Science Guide Chapter 15 Carbon and its Compounds 2

  • This property of carbon itself is the reason for the presence of large number of organic carbon compounds.
  • So organic chemistry essentially deals with catenated carbon compounds.
  • Example: Starch and cellulose contain chains of hundreds of carbon atoms.

Question 2.
What are the chemical reactions of carbon?
Answer:
Elemental carbon undergoes no reaction at room temperature.
Oxidation : Carbon combines with oxygen to form its oxides such as carbon monoxide (CO) and carbon dioxide (CO2), with evolution of heat. Organic carbon compounds like hydrocarbon also undergo oxidation to form oxides and steam with evolution of heat and flame.

This reaction is also called ‘Combustion’.
Samacheer Kalvi 9th Science Guide Chapter 15 Carbon and its Compounds 3

Reaction with Steam : Carbon reacts with steam to form carbon monoxide hydrogen. This mixture is called water gas.
C(S) + H2O(g) → CO(g) + H2(g)

Reaction with Sulphur: With sulphur, carbon forms its disuiphide at high temperature.
C(S) + S(g) → CS2(g)

Reaction with Metals : At elevated temperatures, carbon reacts with some metals like iron, tungsten, titanium, etc., to form their carbides
W(S)+C(g) → WC(S)

 Samacheer Kalvi 9th Science Guide Chapter 15 Carbon and its Compounds
Question 3.
Name the three safer resin codes of plastics and describe their features.
Answer:
Samacheer Kalvi 9th Science Guide Chapter 15 Carbon and its Compounds 4

VI. Higher Order Thinking Skills:

Question 1.
Why do carbon exist mostly in combined state?
Answer:
Carbon is an element that can form many different compounds, as each carbon atom can form 4 chemical bonds with other atoms and because the carbon atom is just the right size to fit in comfortably as parts of very large molecules.

 Samacheer Kalvi 9th Science Guide Chapter 15 Carbon and its Compounds

Question 2.
When a carbon fuel burns in less aerated room, it is dangerous to stay there. Why?
Answer:

  • When a carbon fuel bums in less aerated room, the fuel may undergo incomplete combustion.
  • It results in the formation of carbon monoxide.
  • When exposed to carbon monoxide (CO) it enters human body, through breathing, affects the function of haemoglobin.
  • Sometimes, it will lead to death.

Question 3.
Explain how dioxins are formed? Which plastic-type they are linked to and why they are harmful to humans?
Answer:
Dioxin formation:

  • Dioxin compounds are not created intentionally but are formed inadvertently by a number of human and natural activities.
  • These activities include combustion and incineration, forest fires, chlorine bleaching of pulp and paper, certain types of chemical manufacturing and processing, and other industrial processes.
  • Cigarette smoke, some home-heating systems, and exhaust from vehicles using leaded and unleaded petrol as well as diesel fuels also produce small amounts of dioxins.
  • Burning materials that may contain chlorine such as plastics, wood treated with pentachlorophenol (PCP), pesticide-treated wastes, other chemicals such as polychlorinated biphenols (PCBs), and even bleached paper can produce dioxins.

Their link with plastic :

  • Dioxins are linked with PVC (Polyvinyl Chloride plastics).
  • The most dangerous emissions can be caused by burning PVC, as it releases dioxins.

Harmful effects of Dioxins to humans :

  • Dioxins are the most toxic to human organisms.
  • Dioxins can cause cancer, disrupt the endocrine system, alteration in pituitary and thyroid gland functions, immune suppression, neurobehavioral effects and cause reproductive and developmental effects.
  • They are carcinogenic and a hormone disruptor and persistent, and they accumulate in our body-fat and thus mothers give it directly to their babies via the placenta.

 Samacheer Kalvi 9th Science Guide Chapter 15 Carbon and its Compounds

Question 4.
Yugaa wants to buy a plastic water bottle. She goes to the shop and sees four different kinds of plastic bottles with resin codes 1, 3, 5, and 7. Which one should she buy? Why?
Answer:

  • Yugaa should buy a plastic water bottle with Resin Code No.5, which is considered as one of the safer plastics. It is light and hard.

Reasons to avoid resin codes 1,3,7

  • Bottle with Resin Code 1 is to be used only once. This plastic can release a chemical additive called antimony, which is not good for health.
  • Bottle with Resin Code 3 is the most toxic plastic. It will have a smell of a new shoe. It should be avoided.
  • Bottle with Resin Code 7 has the plastic types PC and ABS which are unsafe and toxic.

Intext Activities

ACTIVITY -1
With the help of your teacher, try to classify the following as organic and inorganic compounds.
HCN, CO2, Propane, PVC, CO Kerosene, LPG, Coconut oil, Wood, Perfume, Alcohol, Na2CO3, CaCO3. MgO, Cotton, Petrol.
Solution:

Inorganic Organic
CO2 Propane
CO Wood, kerosene, coconut oil
MgO Parfume
HCN Alcohol
Na2CO3 Cotton
PVC Petrol
LPG

[End of the activity]

 Samacheer Kalvi 9th Science Guide Chapter 15 Carbon and its Compounds

ACTIVITY – 2

Take a football since it resembles Buckminsterfullerene. Count how many hexagonal and pentagonal panels are in it very comer is considered as one carbon. Compare your observation with fullerene and discuss with your friends.
Aim:
To compare the structure of fullerene with football.
Materials required:
Football

Procedure:

  1. Take football.
  2. Count the hexagonal and pentagonal rings shapes in football.

Observation:

Shapes Fullerene (C60) Football
Pentagon 12 Pentagonal rings 12 Black pentagons
Hexagon 20 Hexagonal rings 20 White hexagons
Structure Closed cage-like structure Polyhedron Structure

Conclusion :
The structure of football is compared with fullerene.

9th Science Guide Carbon and its Compounds Additional Important Questions and Answers

I. Choose the correct answer :

Question 1.
Carbon is one of the most important ………………….element.
(a) Metallic
(b) Non-metallic
(c) Metalloid _
(d) None of these
Answer:
(b) Non-metallic

Question 2.
The most recently discovered allotrope of carbon is ……………….
(a) Graphite
(b) Fullerene
(c) Graphene ‘
(d) Gas carbon
Answer:
(c) Graphene

 Samacheer Kalvi 9th Science Guide Chapter 15 Carbon and its Compounds

Question 3.
……………. is the first organic compound synthesized in the laboratory.
(a) Urea
(b) Acetic acid
(c) Methane
(d) Ethanol
Answer:
(a) Urea

Question 4.
The main component of water gas is …………….
(a) Carbon dioxide
(b) Carbon monoxide
(c) Calcium carbide
(d) Methane
Answer:
(b) Carbon monoxide

 Samacheer Kalvi 9th Science Guide Chapter 15 Carbon and its Compounds

Question 5.
The ability of carbon to form …………… is the main reason for the formation of various classes of carbon compounds.
(a) Tetravalency
(b) Catenation
(c) Isomerism
(d) Multiple bonds
Answer:
(d) Multiple bonds

Question 6.
Arrangement of atoms in diamond is …………………
(a) Hexagonal
(b) Trigonal
(c) Tetrahedral
(d) Pentagonal
Answer:
(c) Tetrahedral

 Samacheer Kalvi 9th Science Guide Chapter 15 Carbon and its Compounds

Question 7.
The amorphous allotropic carbon used for making electrodes in dry cell
(a) Coke
(b) Charcoal
(c) Lampblack
(d) Gas carbon
Answer:
(d) Gas carbon

Question 8.
Elemental carbon undergoes …………. reaction at room temperature.
(a) Oxidation
(b) Reduction
(c) Free radical
(d) no.
Answer:
(d) no

 Samacheer Kalvi 9th Science Guide Chapter 15 Carbon and its Compounds

Question 9.
Amorphous forms of carbon and graphite are almost …………… in colour.
(a) Grey
(b) brownish
(c) black
(d) dirty white
Answer:
(c) black

Question 10.
Carbon monoxide displaces ………………. from hemoglobin.
(a) nitrogen
(b) oxygen
(c) hydrogen
(d) carbon dioxide
Answer:
(b) oxygen

 Samacheer Kalvi 9th Science Guide Chapter 15 Carbon and its Compounds

Question 11.
Burning of PVC releases
(a) Dioxins
(b) Carbon monoxide
(c) Sulphur dioxide
(d) Chlorine
Answer:
(a) Dioxins

Question 12.
Which among the following plastics release antimony when we reuse.
(a) PVC
(b) HDPE
(c) PP
(d) PET
Answer:
(d) PET

Question 13.
According to the Octet rule, carbon requires ……………. electrons to attain the nearest noble gas.
(a) One
(b) two
(c) Three
(d) Four
Answer:
(d) Four

 Samacheer Kalvi 9th Science Guide Chapter 15 Carbon and its Compounds

Question 14.
Most one-time use plates are made from ……………
(a) Polypropylene
(b) Polystyrene
(c) Polyethylene
(d) Polyvinylchloride
Answer:
(b) Polystyrene

Question 15.
Which among the following compound is soluble in water?
(a) Methane
(b) Ethylene
(c) Ethanol
(d) Phenol
Answer:
(c) Ethanol

 Samacheer Kalvi 9th Science Guide Chapter 15 Carbon and its Compounds

Question 16.
The number of free electrons in each carbon of diamond is
(a) Zero
(b) One
(c) Two
(d) None of these
Answer:
(a) zero

Question 17.
The carbon atoms in Graphene are arranged in
(a) Hexagon
(b) Pentagon
(c) octagon
(d) Tetragon
Answer:
(a) Hexagon

 Samacheer Kalvi 9th Science Guide Chapter 15 Carbon and its Compounds

Question 18.
Resin Code” represents the type of …………….. used to make the plastic.
(a) Polymer
(b) Rubber
(c) monomer
(d) Polymerisation
Answer:
a) Polymer

Question 19.
Diamond is not a good conductor of electricity because
(a) it is very hard
(b) it has no free electron
(c) its structure is uniform
(d) it is insoluble in water
Answer:
(b) it has no free electron
Hint: Diamond contains no free electron and it behaves as an insulator

 Samacheer Kalvi 9th Science Guide Chapter 15 Carbon and its Compounds

Question 20.
Which of the following is highly toxic?
(a) Carbon dioxide
(b) Carbon monoxide
(c) Calcium carbonate
(d) Sodium bicarbonate
Answer:
(b) Carbon monoxide
Hint: CO easily binds with Haemoglobin and then causes death

Question 21.
Which of the following plastic items are banned by the Government of Tamil Nadu as of 1st January 2019?
(a) Plastic sheets
(b) Plastic teacups
(c) Plastic water packet
(d) All the above
Answer:
(d) All the above

 Samacheer Kalvi 9th Science Guide Chapter 15 Carbon and its Compounds

Question 22.
Graphite is used as a lubricant in machines because
(a) it is a good conductor of electricity
(b) it is made of slippery layers and  has a high melting point
(c) it has a high density
(d) it is strong and soft
Answer:
(b) it is made of slippery layers and has a high melting point

Question 23.
Plastic resin codes are shown as three chasing arrows in a ………………. with a number in the middle or letters (an acronym of that plastic type).
(a) Logo
(b) Recycling Symbol
(c) Square
(d) Triangle
Answer:
(d) Triangle

 Samacheer Kalvi 9th Science Guide Chapter 15 Carbon and its Compounds

II. Fill in the blanks :

1. …………… is the main constituent of coal.
Answer:
Carbon

2. Carbon chemistry is also called as ……………..
Answer:
Living chemistry

3. Graphene has a thickness of just …………… atom.
Answer:
One

 Samacheer Kalvi 9th Science Guide Chapter 15 Carbon and its Compounds

4. ……………. is the Father of Modem Organic Chemistry
Answer:
Friedrich Wohler

5. The inorganic carbon compound that takes past in photosynthesis is …………………….
Answer:
Carbon dioxide

6. The carbon cycle is the …………….. cycle.
Answer:
Biogeochemical

 Samacheer Kalvi 9th Science Guide Chapter 15 Carbon and its Compounds

7. ……………….. structure accountable for hardness and rigidity of diamond.
Answer:
Three dimensional

8. Hexagonal layers in Graphite are held together by ……………………
Answer:
weak VanderWaals forces

9. Pet name for Buckminster Fullerene is ………………….
Answer:
Bucky ball

 Samacheer Kalvi 9th Science Guide Chapter 15 Carbon and its Compounds

10. A large family of fullerene exists, starting at ………………… and reaching upto .
Answer:
C20, C540

11. Graphene is ………………. shaped hexagonal ring
Answer:
Honeycomb

12. Cigarette smoking is a source of ……………….
Answer:
Carbon Monoxide

 Samacheer Kalvi 9th Science Guide Chapter 15 Carbon and its Compounds

13. Carbon monoxide enters into human body through …………………
Answer:
breathing

14. Do not use _______ for school projects.
Answer:
Thermocol

15. Polycarbonate (PC) plastic contains ……………..
Answer:
Bisphenol A

 Samacheer Kalvi 9th Science Guide Chapter 15 Carbon and its Compounds

III. Match the following :
(I)

1. Graphite a) Honeycomb
2. Fullerene b) Tetrahedral
3. Graphene c) Hexagonal
4. Diamond d) Dome-shaped

Answer:
1 – c, 2 – d, 3 – a, 4 – b

(II)
Samacheer Kalvi 9th Science Guide Chapter 15 Carbon and its Compounds 5
Answer:
1-b,2-c,3-a,4-d

(III)
Samacheer Kalvi 9th Science Guide Chapter 15 Carbon and its Compounds 6
Answer:
1-c, 2 -a, 3-b, 4-c

IV. True or False :

1. About 18% of the weight of the human body is carbon.
Answer:
True.

2. There is more abundance of carbon in the earth
Answer:
False.
Correct statement: There is less abundance of carbon in the earth.

 Samacheer Kalvi 9th Science Guide Chapter 15 Carbon and its Compounds

3. Carbon has the tendency to lose its four electrons with that of other atoms to complete its octet.
Answer:
False.
Correct statement: Carbon has the tendency to share its four electrons with that of other atoms to complete its octet

4. All the allotropic forms of carbon are solids.
Answer:
True.

5. Carbon’s amorphous forms have high melting and boiling poult compared to crystalline forms.
Answer:
False.
Correct statement: Carbon’s amorphous forms have low melting and boiling point compared to crystalline forms.

 Samacheer Kalvi 9th Science Guide Chapter 15 Carbon and its Compounds

6. Used plate is easy to recycle.
Answer:
False.
Correct statement: Used plate difficult to recycle.

7. Do not eat hot food items in plastic containers.
Answer:
True.

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 the reason is not the correct explanation of assertion.
(c) If Assertion is true but the reason is false.
(d) Both assertion and reason are false.

Question 1.
Assertion (A) : The number of carbon compounds alone is more than the number of compounds of all the elements taken together.
Reason (R) : Carbon has some unique properties such as
1) Catenation, 2) Tetravalency, 3) Multiple bonds, 4) Allotropy, 5) Isomerism.
Answer:
(a) Both Assertion and Reason are true and Reason is the correct explanation for Assertion

 Samacheer Kalvi 9th Science Guide Chapter 15 Carbon and its Compounds

Question 2.
Assertion (A) : There are various classes of carbon compounds formed.
Reason (R) : The property of Isomerism is the main reason.
Answer:
(c) Assertion is true but reason is false
Reason : The ability to form multiple bonds is the main reason.

Question 3.
Assertion (A) : Carbon monoxide is a toxic gas of carbon.
Reason (R): smoking is a source of carbon monoxide.
Answer:
(b) Both assertion and reason are true but reason is not the correct explanation for assertion

Question 4.
Assertion (A): PVC is an unsafe plastic.
Reason (R)Burning PVC releases dioxins, a most toxic chemical.
Answer:
(a) Both Assertion and Reason are true and Reason is the correct explanation for Assertion

 Samacheer Kalvi 9th Science Guide Chapter 15 Carbon and its Compounds

VI. Answer the following by rearranging the jumbled letters :

Question 1.
It is the hardest allotrope of carbon
mnodaid
Answer:
Diamond

Question 2.
Organic compounds having a double bond between carbon atoms are
knelaes
Answer:
Alkenes

 Samacheer Kalvi 9th Science Guide Chapter 15 Carbon and its Compounds

Question 3.
Reaction of carbon with oxygen gives
osdiex
Answer:
Oxides

Question 4.
In this molecule, carbon is attached to four hydrõgen atoms.
emathen
Answer:
Methane

 Samacheer Kalvi 9th Science Guide Chapter 15 Carbon and its Compounds

Question 5.
Carbon combines with other elements through the _______ bond.
lnaocvet
Answer:
Covalent

Question 6.
Plastics made of________ are represented by resin code #6.
sytlopynere
Answer:
Polystyrene

Question 7.
One-time use plastics are also known as ______ plastics.
áwyrhotwa
Answer:
throwaway

 Samacheer Kalvi 9th Science Guide Chapter 15 Carbon and its Compounds

Question 8.
One-time use plastics cause ________ damage.
trnvomenialne
Answer:
Environmental

Question 9.
Expanded polystyrene is commercially known as
mthreolco
Answer:
Thermocol

 Samacheer Kalvi 9th Science Guide Chapter 15 Carbon and its Compounds

VII. Very Short Answer questions :

Question 1.
How can graphite be transformed to diamond?
Answer:
Graphite could be transformed to the diamond at high temperature and high pressure.

Question 2.
How did the ancients obtain charcoal?
Answer:
Ancients manufactured charcoal by burning organic compounds.

Question 3.
Which theory was challenged by the synthetic preparation of Urea?
Answer:
Vital force theory.

 Samacheer Kalvi 9th Science Guide Chapter 15 Carbon and its Compounds

Question 4.
Name two inorganic carbon compounds which are used as an antacid?
Answer:
Calcium carbonate (CaCO3), Sodium bicarbonate (NaHCO3)

Question 5.
What is tetravalency?
Answer:
Carbon has the tendency to share~its four electrons with other atoms to complete its octet. This is called Tetravalency.

Question 6.
Name the primary factor that determines the physical and chemical properties of compounds.
Answer:
Nature of bonding in a compound.

 Samacheer Kalvi 9th Science Guide Chapter 15 Carbon and its Compounds

Question 7.
Why do elements show allotropy?
Answer:
It’s a method of formation or preparation.

Question 8.
Why is graphite softer than a diamond?
Answer:
The hexagonal layers in graphite are held together by weak Vander Waals forces of attraction.

Question 9.
What are Polymer resins?
Answer:
Plastics, made from long-chain organic compounds, are called “Polymer resins”.

 Samacheer Kalvi 9th Science Guide Chapter 15 Carbon and its Compounds

Question 10.
List the three unsafe plastics.
Answer:

  1. Polyvinyl chloride (PVC)
  2. Polystyrene (Thermocol)
  3. Polycarbonates (PC).

Question 11.
How many valence electrons are there in carbon?
Answer:
There are 4 valence electrons in carbon, out of 6 total electrons.

Question 12.
Who is called ‘Father of Modern Organic Chemistry’?
Answer:
Friedrich Wohler is called the ‘Father of Modern Organic Chemistry’.

 Samacheer Kalvi 9th Science Guide Chapter 15 Carbon and its Compounds

Question 13.
Which three resin codes are unsafe?
Answer:
Resin Code Nos. 3, 6, and 7 unsafe.

VIII. Short Answer questions:

Question 1.
Prove that a diamond is a pure form of carbon?
Answer:

  • When an equal weight of charcoal and diamond were burned, they produced the same amount of carbon dioxide.
  • So like charcoal, diamond is also a pure form of carbon.

Question 2.
Write the classification of carbon compounds.
Answer:

1. Organic Carbon Compound 2. Inorganic Carbon Compounds
These are the compounds of carbon obtained from living organisms such as plants and animals.
(e.g) Cellulose, Ethanol, Starch.
These are the compounds containing carbon but obtained from non-living matter.
(e.g) Calcium carbonate, Carbon dioxide, Carbon monoxide

Question 3.
Write short notes on the carbon cycle.
Answer:

  1. The carbon cycle is the biogeochemical cycle.
  2. Carbon is exchanged among the biosphere, geosphere, hydrosphere, and atmosphere of the Earth.
  3. Carbon is the main component of biological compounds as well as a major component of many minerals such as limestone.

 Samacheer Kalvi 9th Science Guide Chapter 15 Carbon and its Compounds

Question 4.
Define: (i) Allotropy (ii) Allotrope
Answer:
(i) Allotropy: It is a property by which an element can exist in more than one form that is physically different and chemically similar.
(ii) Allotrope: The different forms of an element.

Question 5.
Differentiate crystalline and amorphous forms of allotropes of carbon.
Answer:

Crystalline allotropes of carbon Amorphous allotropes of carbon
1. Diamond 1. Charcoal
2. Graphite 2. Lampblack
3. Fullerene 3. Coke
4. Graphene 4. Gas Carbon

Question 6.
Why is carbon monoxide harmful to health? (or) What happens when we breath Carbon monoxide?
Answer:

  • On exposition, carbon monoxide (CO) enters the human body through breathing.
  • It affects the function of hemoglobin by displacing oxygen from hemoglobin.
  • It will lead to death.

 Samacheer Kalvi 9th Science Guide Chapter 15 Carbon and its Compounds

Question 7.
Why. do we remove plastics safely? How can it be done?
Answer:

  • Plastics are non-biogradable.
  • Plastics can be recycled (or) disposed safely without harming environment.

Question 8.
Mention two reasons for the harmful nature of plastics.
Answer:

  1. Plastics contain chemicals that are harmful to our health.
  2. Most of the plastics are one-time use (or) throwaway in nature and pollutes the environment.

Question 9.
Give some examples of one-time-use plastic.
Answer:

  • Plastic carry bags,
  • Cups,
  • Plastic plates,
  • Straws,
  • Water pouches, 6. Plastic sheets.

 Samacheer Kalvi 9th Science Guide Chapter 15 Carbon and its Compounds

Question 10.
What we can do to prevent plastic pollution?
Answer:

  • Share scientific knowledge on plastics and their effects with our family, friends, and relatives.
  • Create awareness to avoid harmful plastics by educating about the resin codes.
  • Educate about the new rules to stop one-time use of plastics.

IX. Long Answer questions

Question 1.
Draw a timeline of carbon chemistry depicting the contribution by scientists.
Answer:

Year Scientist Contribution
1772 Antoine Lavoisier (France) Diamond and charcoal are carbon allotropes
1779  Carl Scheele (Sweden) Graphite is another form of carbon
1796 Smithson Tennant Diamond is a pure carbon like charcoal.
1855 Benjamin Brodie (England) Pure graphite from carbon, proving graphite is a form of carbon
1955 Francis Bundy (USA) Transformed graphite into diamond.
1985 Robert Curl, Harry Kroto and Richard Smalley Discovered a new form of carbon called fullerenes.
2004 KostyaNovoselov Andre Geim Graphene – lightest carbon

 Samacheer Kalvi 9th Science Guide Chapter 15 Carbon and its Compounds

Question 2.
Give an account of (I) Isomerism (II) Isomers with an illustration.
Answer:
(1) Isomerism: The Phenomenon in which an element has the same molecular formula may exhibit different structural arrangement is called Isomerism.
(II) Isomers: Compounds that have the same molecular formula but different structural formula are called isomers.
Illustration: Molecular formula: C2H6O, is having two kinds of the arrangement of atoms as shown below.

Samacheer Kalvi 9th Science Guide Chapter 15 Carbon and its Compounds 7

In the above illustration, the molecular formula C2H6O has two different structural formulae
(a) Alcohol (CH3CH2OH) [Oxygen at the end of Chain
(b) Ether (CH3OCH3) [Oxygen at the middle
Both structural formulae will show different physical and chemical properties.

Question 3.
Write the salient features of Graphene.
Answer:

  • Graphene is the most recently produced allotrope of carbon.
  • It is honey comb-shaped hexagonal rings repeatedly arranged in a plane.
  • It is the thinnest compound known to man at one atom thick.
  • It is the lightest material known and the strongest compound discovered.
  • Layers of graphene are stacked to form graphite by Vander Waals forces.

Question 4.
Briefly note the harmful effects of any four plastics.
Answer:
Samacheer Kalvi 9th Science Guide Chapter 15 Carbon and its Compounds 8

 Samacheer Kalvi 9th Science Guide Chapter 15 Carbon and its Compounds

Question 5.
How can you minimise plastic pollution by your daily practices?
Answer:

  • Don’t litter the environment by throwing plastic items.
  • Don’t burn plastics since it causes the evolution of highly toxic gases.
  • Avoid one-time use (or) throw away plastics like plastic bags, teacups, carry bags, plastic plates, etc.
  • Don’t eat hot (or) spicy food items in plastic containers. ‘
  • Segregate the plastic wastes and hand this over to the municipal authorities so that it can be recycled.
  • Know about the resin codes and avoid unsafe plastics.
  • Don’t use thermocol for school projects.

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