Samacheer Kalvi 11th Bio Botany Guide Chapter 13 Photosynthesis

Tamilnadu State Board New Syllabus Samacheer Kalvi 11th Bio Botany Guide Pdf Chapter 13 Photosynthesis Text Book Back Questions and Answers, Notes.

Tamilnadu Samacheer Kalvi 11th Bio Botany Solutions Chapter 13 Photosynthesis

11th Bio Botany Guide Photosynthesis Text Book Back Questions and Answers

PART-I

Question 1.
Assertion (A): Increase in proton gradient inside lumen responsible for ATP synthesis
Reason (R): Oxygen evolving complex of PSI located on thylakoid membrane facing Stroma, releases H+ ions
a) Both Assertion and Reason are True
b) Assertion is Tine and Reason is False
c) Reason is True Assertion is False
d) Both Assertion and Reason are False
Answer:
(b)

Question 2.
Which chlorophyll molecule does not have a phytol tail?
a) Chl – a
b) Chl – b
c) Chl – c
d) Chl – d
Answer:
(c)

Samacheer Kalvi 11th Bio Botany Guide Chapter 13 Photosynthesis

Question 3.
The correct sequence of flow of electrons in the light reaction is
a) PS II, Plastoquinone, cytochrome PS I, ferredoxin
b) PS I, plastoquinone, cytochrome, PS II, ferredoxin.
c) PS II, ferredoxin, plastoquinone, cytochrome, PS I.
d) PS I, plastoquinone, cytochrome, PS II, ferredoxin
Answer:
(a)

Question 4.
For every CO2 molecule entering the C3 cycle, the number of ATP & NADPH required
a) 2ATP + 2NADPH
b) 2ATP + 3NADPH
c) 3ATP + 2NADPH
d) 3ATP + 3NADPH
Answer:
(c)

Samacheer Kalvi 11th Bio Botany Guide Chapter 13 Photosynthesis

Question 5.
Identify true statement regarding light reaction of photosynthesis?
a) Splitting of water molecule is associate with PS I.
b) PS I and PS II involved in the formation of NADPH + H+
c) The reaction center of PSI is Chlorophyll a with absorption peak at 680nm.
d) The reaction center of PS II is Chlorophyll a with absorption peak at 700 nm.
Answer:
(b)

Question 6.
Two groups (A&B) of bean plants of similar size and same leaf area were placed in identical conditions. Group A was exposed to light of wavelength 400 – 450 nm & Group B to light of wavelength of 500 – 550nm. Compare the photosynthetic rate of the 2 groups giving reasons.
Answer:
‘A group of plants exposed to light of 400 – 450nm. Chlorophyll a shows maximum absorption peak at 450nm (blue region). Hence rate of photosynthesis was high.
‘B’ group of plants exposed to light of 500 – 550nm. This wavelength refers to green region of the spectrum. Chlorophyll does not absorb light in the green region but reflects green. So plants appear green rate of photosynthesis was negligible in these plants.

Samacheer Kalvi 11th Bio Botany Guide Chapter 13 Photosynthesis

Question 7.
A tree is believed to be releasing oxygen during night time. Do you believe the truthfulness of this statement? Justify your answer by giving reasons?
Answer:
It is a belief that some trees such as Aloe vera Peepal tree, some palm varieties grown as indoor plants release oxygen during night time. There is no scientific evidence for this So it is not true. This is because oxygen is evolved during the light reaction of photosynthesis only. This reaction occurs only in the presence of light. Therefore oxygen cannot be released during night time.

Question 8.
Grasses have an adaptive mechanism to compensate photorespiratory losses – Name and describe the mechanism.
Answer:
The photorespiratory losses are checked by certain grasses by having physiological adaptation. The process of photosynthesis occurs in mesophyll cells and bundle sheath cells.

Mesophyll cells :
a) Initially CO2 is taken up by Phosphoenolpyruvate (PEPA) (3C) and changed to oxaloacetate (4C) in the presence of PEP carboxylase.
b) Oxaloccetate is reduced to Malate/Aspartate. The product formed reaches the bundle sheath.

Bundle Sheath:
a) The oxidation of Malate and Aspartate occurs with release of carbon dioxide and formation of Pyruvate (3C)
b) Due to increased CO2 concentration RUBISCO, functions as carboxylase and not as Oxygenase.
c) The photosynthetic losses are prevented.
d) RUBP operates now under Calvin cycle and pyruvate transported back to Mesophyll cells is changed into Phosphoenol pyruvate to keep the cycle going.

Samacheer Kalvi 11th Bio Botany Guide Chapter 13 Photosynthesis

Question 9.
In Botany class, teacher explains, Synthesis of one glucose requires 30 ATPs in C4 plants and only 18 ATPs in C3 plants. The same teacher explains C4 plants are more advantageous than C3 plants. Can you identify the reason for this contradiction?
Answer:
C4 Plants are more advantageous than C3 plants because of the following reasons:

C4 Plants C3 Plants
CO2 fixation occurs in mesophyll cells only CO2 fixation occurs in mesophyll and bundle sheath cells
RUBP is the only CO2 acceptor PEPA Phosphoenol pyruvate in mesophyll is the acceptor in the first phase
Fixation of C02 occurs if the atmospheric concentration of C02 is 50 ppm only It can fix carbon dioxide even if the atmospheric concentration of CO2 is below 10 ppm
Optimum temperature is 20° to 25°C Optimum temperature is 30° to 45°C and is thus effective in tropical regions.
 RUBP carboxylase enzyme also functions as oxygenase if the 0, concentration is higher than carbon dioxide PEP carboxylase enzyme functions even at low carbon – dioxide concentrations.
Higher rate of photorespiration and hence rate of photosynthesis is reduced. Minimal rate of photorespiration is seen is C4 plants.

Question 10.
When there is plenty of light and higher concentration of O2, what kind of pathway does the plant undergo? Analyse the reasons.
Answer:
Photorespiration is the excess respiration taking place in photosynthetic cells due to absence of CO2 and increase of O2. This condition changes the carboxylase role of RUBISCO (RUBP carboxylase oxygenase) enzyme into oxygenase. C2 cycle or photorespiration, begins and operates in the chloroplast, Peroxisome and Mitochondria.
It protects, photosynthetic cells from photooxidative damage.

Part-II.

11th Bio Botany Guide Photosynthesis Additional Important Questions and Answers

I. Choose the Correct Answers

Question 1.
The radiation that reaches the earth & the visible spectrum …….. are
a) 300 to 2600 nm & 390 to 793 nm
b) 390to763nm & 560to987nm
c) 440to l600nm & 770to689nm
d) 480 to 1800 nm & 660 to 978 nm
Answer:
a) 300 to 2600 nm & 390 to 763 nm

Question 2.
Physiological unit of photosynthesis is
a) 150-250 Chlorophyll molecules
b) 200-300 chlorophyll molecules
c) 440-660 chlorophyll molecules
d) 450- 650 chlorophyll molecules
Answer:
b) 200-300 chlorophyll molecules

Samacheer Kalvi 11th Bio Botany Guide Chapter 13 Photosynthesis

Question 3.
The number of chlorophyll molecules required to fix one molecules of CO2 are
a) 1500
b) 2500
c) 3500
d) 4400
Answer:
b) 2500

II. Match Correctly & Choose The Right Answer

Question 4.
I) Black Mann – A) importance of Chlorophyll
II) Warburg – B) Law of limiting factor
III) Dustrochet – C) C4 cycle
IV) Hatch & Slack – Chlorella
Samacheer Kalvi 11th Bio Botany Guide Chapter 13 Photosynthesis 1
Answer:
c) B-D-A-C

Samacheer Kalvi 11th Bio Botany Guide Chapter 13 Photosynthesis

Question 5.
Carotenoids are mostly
a) Methyl group of chemicals
b) Ferric compounds
c) Tetra terpenes
d) Triterpenoids
Answer:
c) Tertra terpenes

Question 6.
The pigment responsible for yellowing of leaves during autumn season is
a) Violaxanthin
b) Fucoxanthin
c) Phycobillin
d) Lycopene
Answer:
d) Lycopene

Samacheer Kalvi 11th Bio Botany Guide Chapter 13 Photosynthesis

Question 7.
The no of quanta of light required for the re-lease of one oxygen molecule
a) 18 quanta
b) 8 quanta
c) 81 quanta
d) 19 quanta
Answer:
b) 8 quanta

Question 8.
ATP required to release electron is
a) 48 ATP
b) 22 ATP
c) 12 ATP
d) 18 ATP
Answer:
d) 18 ATP

Samacheer Kalvi 11th Bio Botany Guide Chapter 13 Photosynthesis

Question 9.
RUBISCO – Constitute …………. of chloroplast protein
a) 17%
b) 20%
c) 18%
d) 16%
Answer:
d) 16%

Question 10.
One complete light reaction involves ……………….. quanta of light
a) 50
b) 45
c) 48
d) 90
Answer:
c) 48

Samacheer Kalvi 11th Bio Botany Guide Chapter 13 Photosynthesis

Question 11.
According to Emerson the fall in quantum yield about 680 nm is called
a) Phoisynthtic drop
b) Emerson drop
c) Airburg effect
d) Red drop
Answer:
d) Red drop

Question 12.
The 5C – primary acceptor of CO2 in Calvin cycle is
a) OAA
b) RUBP
c) PEA
d) RUBISCO
Answer:
b) RUBP

Samacheer Kalvi 11th Bio Botany Guide Chapter 13 Photosynthesis

Question 13.
Which of the following equation correctly sums up photosynthesis
Samacheer Kalvi 11th Bio Botany Guide Chapter 13 Photosynthesis 2
Answer:
Samacheer Kalvi 11th Bio Botany Guide Chapter 13 Photosynthesis 3

Question 14.
Water splitting is concerned with photosystem
a) P.S I
b) P.S II
c) Both (a) & (b)
d) P.S II
Answer:
b) P.S II

Question 15.
Which photosystem is found to be located on the outer surface of thylakoid?
a) PS I
b) P.S II
c) P890
d) Both (a) and (b)
Answer:
a) P.S I

Samacheer Kalvi 11th Bio Botany Guide Chapter 13 Photosynthesis

Question 16.
Photosystem usually involved in both cyclic and non – cyclic phosphorylation is
a) PS-I
b) PS II
c) Both (a) & (b)
d) P890
Answer:
b) PS II

Question 17.
The term Quantosome was coined by
a) Emerson
b) Liebig
c) Calvin & Melvin
d) Park & Biggins
Answer:
d) Park & Biggins

Samacheer Kalvi 11th Bio Botany Guide Chapter 13 Photosynthesis

Question 18.
C3 cyclic is not known as
a) Dark reaction
b) Bio synthetic phase
c) P C.R. Cycle
d) CAM Cycle
Answer:
d) CAM Cycle

Question 19.
Photosynthesis produces
a) 1700 million tonnes of dry matter/year by fixing 75 x 1012 kg of carbon every year
b) 7100 million tonnes of dry matter/year by fixing 75 x 1012 kg of carbon every year
c) 1600 million tonnes of dry matter/week by fixing 56 x 1210 kg of carbon every week
d) 6100 million tonnes of dry matter/month by fixing 100 x 1012 kg of carbon every month
Answer:
a) 1700 million tonnes of dry matter/year by fixing 75 x 1012 kg of carbon every year

Question 20.
Maximum O2 evolution occur from
a) forests
b) Marine phyto plankton
c) Crops
d) Land mass
Answer:
b) Marine phyto plankton

Samacheer Kalvi 11th Bio Botany Guide Chapter 13 Photosynthesis

Question 21.
Products of light reaction in photosynthesis are
a) ATP & NADPH2
b) ADP & glucose
c) Ferredoxin and cytochrome b6
d) Cytochrome
Answer:
a) ATP & NADPH2

Question 22.
Photo reaction centres in higher plants are
a) P700
b) P 680
c) Both a & b
d) Chlorophyll a
Answer:
c) Both a & b

Samacheer Kalvi 11th Bio Botany Guide Chapter 13 Photosynthesis

Question 23.
Photosynthetic pigments in chloroplasts lie embedded in
a) Chloroplast envelope
b) Plastogloblue
c) matrix
d) thylakoids
Answer:
d) thylakoids

Question 24.
Water soluble pigment is
a) Chlorophyll
b) Carotene
c) Phycobillin
d) Xanthophyll
Answer:
c) Phycobillin

Samacheer Kalvi 11th Bio Botany Guide Chapter 13 Photosynthesis

Question 25.
Carotenoids and Xanthophylls are also known as
a) Respiratory pigments
b) Accessory pigments
c) Photosynthetic pigments.
d) Photolytic pigments
Answer:
b) Accessory pigments

Question 26.
Which metal ion is a
a) Iron
b) cobalt
c) Magnesium
d) Zinc
Answer:
c) Magnesium

Samacheer Kalvi 11th Bio Botany Guide Chapter 13 Photosynthesis

Question 27.
The site of photophosphorylation in Chloroplast is
a) granum
b) matrix
c) chloroplast surface
d) None of these
Answer:
a) granum

Question 28.
The process of photophosphorylation was discovered by
a) Priestly
b) Calvin
c) Amon
d) Warburg
Answer:
c) Arnon

Samacheer Kalvi 11th Bio Botany Guide Chapter 13 Photosynthesis

Question 29.
Which of the following is a C4 plant
a) Potato
b) Sugarcane
c) Pea
d) Papaya
Answer:
b) Sugarcane

Question 30.
Agranal chloroplasts are characteristics of
a) Mesophyll of pea leaves
b) Bundle sheaths of Mango leaves
c) Mesophyll of Maize leaves
d) Bundle sheath of sugarcane leaves
Answer:
d) Bundle sheath of sugarcane leaves.

Samacheer Kalvi 11th Bio Botany Guide Chapter 13 Photosynthesis

Question 31.
Dimorphism in chloroplasts is seen in
a) C4 plants
b) C2 plants
c) CAM – plants
d) C3 plants
Answer:
a) C4 plants

Question 32.
Energy required for ATP synthesis in PSII comes from
a) Proton gradient
b) Electron gradient
c) Reduction of glucose
d) Oxidation of glucose
Answer:
a) Proton gradient

Samacheer Kalvi 11th Bio Botany Guide Chapter 13 Photosynthesis

Question 33.
The by product of Photosynthesis is
a) O2
b) CO2
c) Carbohydrate
d) EfO
Answer:
a) O2

Question 34.
Which of the following process is called reverse of Glycolysis?
a) CO2 reduction
b) RUBP carboxylation
c) RUBP regeneration
d) ATP synthesis
Answer:
a) CO2 reduction

Samacheer Kalvi 11th Bio Botany Guide Chapter 13 Photosynthesis

Question 35.
The Dark reaction of Photosynthesis occurs in
a) Matrix
b) Grana
c) Stroma
d) Cytoplasm
Answer:
c) Stroma

Question 36.
A granal chloroplasts are characteristics of
a) Mesophyll of pea leaves
b) Bundle sheath of Mango leaves
c) Mesophyll of maize leaves
d) Bundle sheath of sugar cane leaves
Answer:
d) Bundle sheath of Sugar cane leaves

Question 37.
Which of the following plant is a better photosyntehesiser?
a) Mango
b) Sugarcane
c) Wheat
d) Rice
Answer:
b) Sugarcane

Samacheer Kalvi 11th Bio Botany Guide Chapter 13 Photosynthesis

Question 38.
The enzyme that is not found in a C3 plant is
a) RUBP carboxylase
b) PEP carboxylase
c) NADP reductase
d) ATP synthase
Answer:
b) PEP carboxylase

Question 39.
Which of the following factors affect rate of photosynthesis?
I. Light
II. Protoplasmic factor
III. Hormones Codes
IV. Haemoglobin
a) only III
b) I and II
c) only IV
d) I, II and III
Answer:
d) I, II and III

Samacheer Kalvi 11th Bio Botany Guide Chapter 13 Photosynthesis

Question 40.
Match the following columns

Column I Column II
I. The 5C sugar that A. RUBIS Co
II. 3 C sugar that gives Calvin cycle  its nickname B. Glyceraldehyde 3 phosphate
III. Activated form of  3 PGA C. 3 phospho glyceric acid
IV. Huge enzyme complex that bring CO2 and a 5C sugar together. D. RUBP

Samacheer Kalvi 11th Bio Botany Guide Chapter 13 Photosynthesis 4

Question 41.
One complete light reaction involves light energy.
a) 30 quanta
b) 48 quanta
c) 40 quanta
d) 25 quanta
Answer:
b) 48 quanta

Question 42.
During phtosynthesis which of the following event does not take place?
a) oxidation of CO2
b) Reduction of CO2
c) oxidation of H2O
d) Light absorption
Answer:
a) Oxidation of CO2

Samacheer Kalvi 11th Bio Botany Guide Chapter 13 Photosynthesis

Question 43.
The site of light trapping in chloroplast is
a) Thylakoid membrane
b) Stroma
c) Plasma fluid
d) Stromal lamellae
Answer:
a) Thylakoid membrane

Question 44.
Kranz anatomy is traced in the Leaves of
a) Wheat
b) Potato
c) Mustard
d) Sugarcane
Answer:
d) Sugarcane

Samacheer Kalvi 11th Bio Botany Guide Chapter 13 Photosynthesis

Question 45.
The intermediate got from Kreb’s cycle that is used for chlorophyll synthesis is
a) Citric acid
b) Isocitric acid
c) Succinic acid
d) Fumaric acid
Answer:
c) Succinic acid

Question 46.
Existence of light and dark reaction of photosynthesis was proved by
a) Blackman
b) Emerson
c) Warburg
d) Arnon
Answer:
a) Blackman

Samacheer Kalvi 11th Bio Botany Guide Chapter 13 Photosynthesis

Question 47.
Choose the wrong match.
a) Hatch & Slack – Dicarboxylic acid pathway
b) Decker – PCO cycle
c) Ruben, Kamen – CAM cycle
d) Calvin Benson – PCR cycle
Answer:
c) Ruben, Kamen – CAM cycle

Question 48.
I) Primary CO, acceptor – PEPA
II) 4C compound produced 1 st – OAA
III) 1st carboxylation occur in – Bundle sheath cells
IV) 2nd carboxylation occur in – Mesophy 11 cells
a) I & II
b) II & III
c) III & IV
d) I & IV
Answer:
c) III & IV

Question 49.
Say True or False with respect to C2 cycle
I) RUBISCO has the most abundant protein on earth.
II) Photo respiration does not yield any free energy in the form of ATP
III) The end product is 2 – c compound. So the cycle is known as C2 cycle
IV) Under certain condition 50% of the photosynthetic potential is lost because of photo respiration.
Samacheer Kalvi 11th Bio Botany Guide Chapter 13 Photosynthesis 5
Answer:
b) True – True – False – True

Question 50.
Say True or False and choose the right option from the given choice.
I) PAR is between – 400 – 700 mil.
II) Heliophytes (Beans) require higher light intensity than sccophytes (oxalis)
III) Red light induces lowest rate of photosynthesis.
IV) Green light induces highest rate of photosynthesis.
Samacheer Kalvi 11th Bio Botany Guide Chapter 13 Photosynthesis 6
Answer:
c) True – True – False – False

Samacheer Kalvi 11th Bio Botany Guide Chapter 13 Photosynthesis

Question 51.
Choose the wrongly matched pair
a) Stephen hales – Father of plant physiology
b) Lavoisier – Purifying gas oxygen is produced in sun light
c) Vonmayer – Green plants convert solar energy into chemical energy
d) Emerson &Amoid – C4 cycle
Answer:
d) Emerson & Arnold – C4 cycle

Question 52.
Choose the rightly matched pair
a) Chlorophyll a – Accessory pigments and trap solar energy
b) Chlorophyll b – Differs from Chlorophyll a in having CH3 instead of CHO – at 3rd C atom
c) Chlorophyll c – Differs from Chlorophyll a by lacking a phytol tail
d) Chlorophyll d – It has CHO at 3rd at the 3rd carbon atom at 11 – pyrrole ring
Answer:
c) Chlorophyll c – Differs from chlorophyll a by lacking a phytol tail.

Samacheer Kalvi 11th Bio Botany Guide Chapter 13 Photosynthesis

Question 53.
Choose the right matched pairs from the given options.
I) Green non sulphur bacteria – Clostridium & Lynbya
II) Green sulphur bacteria – Chlorobacterium & Chlorobium
III) Purple sulphur bacteria – Thiospirillum & Chromatium
IV) Purple non sulphur bacteria – Rhodopseudomonas & Rhodospirillum
a) I, II, & III
b) II, III & IV
C) I, II & IV
d) I, III & IV
Answer:
b) II, III & IV

II. ASSERTION (A) & REASON (R)

a)Assertion (A) and Reason (R) are true and Reason (R) is the correct explanation of Assertion
b) Both Assertion (A) and Reason (R) are true – Reason is not the correct explanation of Assertion.
c) Assertion (A) is false but Reason (R) is true.
d) Both Assertion (A) and Reason (R) are false.

Question 1.
Assertion (A): Chlorophyll appears green.
Reason (R): It absorbs light mainly in the region of green part of light spectrum.
Answer:
c) Assertion (A) is False but Reason (R) is true.

Samacheer Kalvi 11th Bio Botany Guide Chapter 13 Photosynthesis

Question 2.
Assertion (A): Red of spectrum contains high energy.
Reason (R): Green light of Visible spectrum contain low energy than red light.
Answer:
c) Assertion (A) is False but Reason (R) is true.

Question 3.
Assetion (A): Non cyclic photo phosphorylation occurs in the stroma of chloroplasts
Reason (R): There is a continuous flow of electrons in this process.
Answer:
d) Both Assertion (A) and Reason (R) are false.

Question 4.
Assetion (A): Carotenes and Xanthophylls are soluble in either
Reason (R): These are accessory pigments of photosynthesis
Answer:
b) Both Assertion (A) and Reason (R) are true, Reason is not the correct explanation of Assertion

Question 5.
Assetion (A): Carotenoids are accessory pigments
Reason (R): Absorbed light energy is transferred to reaction centre by carotenoids.
Answer:
a) Assertion (A) and Reason (R) True and Reason is the correct explanation of Assertion.

2 Mark Questions

III.

Question 1.
What is Bioluminescence? or Chemiluminescence?
Answer:
Bioluminescence is the production and emission of light by a living organism. Bioluminescence is rare in true plants – Eg. Fire flies, glow worms etc. – Also observed in some fungi.

Question 2.
What is PAR?
Answer:
It refers to Photosynthetically Active Radiation, which is between 400 – 700 nm photosynthetic rate is maximum in blue and red light – Green light induces lowest rate of photosynthesis.

Samacheer Kalvi 11th Bio Botany Guide Chapter 13 Photosynthesis

Question 3.
Name the Photosyntheic pigments of Bacteria
Answer:
Bacterio chlorophyll a, Bacterio chlorophyll b, Chlorobium chlorophyll 650, Chlorobium chlorophyll 666.

Question 4.
Name the photosynthetic pigments of Algae?
Answer:

  • Chlorophyll b – Green Algae
  • Chlorophyll c – Dianoflagellates, Diatoms & Brown Algae
  • Chlorophyll d – Red Algae
  • Chlorophyll e – Xantho phycean Algae.

Question 5.
What is Emerson’s Enhancement Effect (EEE)?
Answer:

  • Emerson found when monochromatic light of longer wavelength (Farred) When supplemental with shorter
    wave length (red light) enhanced the photosynthetic yield and recovered red drag. ,
  • This enhancement of photosynthetic yield is referred to as EEE.
    I) P. S – yield of farred light (71 Onm) =10
    II) PS- yield of red light (65Qnm) = 43.5
    (I) + (II) = 72.5
  • EEE = 72.5

Samacheer Kalvi 11th Bio Botany Guide Chapter 13 Photosynthesis

Question 6.
Write down the significance of photorespiration.
Answer:

  • Glycine and Serine synthesised during this process are precursors of many bio molecules like Chlorophyll,
    Proteins, Nucleotides. ‘
  • It consumes excess NADH + H+ generated.
  • Glycolate protect cells from Photo oxidation.

Question 7.
What are the conclusions of Hill’s Reaction.
Answer:

  • During Photosynthesis oxygen is evolved from water.
  • Electrons for the reduction of CO2 are obtained from water.
  • Reduced substance produced, later helps to reduce CO2
    2H2O + 2 A→ 2 AH2 + O2

Question 8.
What is carbon di oxide compensation point?
Answer:

  • Carbon di oxide compensation point is that point at which the rate of Photosynthesis equals the rate of Respiration.
  • At this point there is no exchange of oxygen and carbon di oxide.
  • It occur when light is not the limiting factor and the concentration of CO2 is 50 -100 ppm.

Question 9.
Notes on Phycobillins.
Answer:

  • They are proteinaceous pigments.
  • They are soluble in water.
  • Lack ‘Mg’ and phytol tail.

There are 2 forms

  1. Phycocyanin
  2. Phycoerythrin.
  • Phycocyanin occur in Cyanobacteria.
  • Phyco erythrin occur in Rhodophycean Algae.

Question 10.
What is meant by non – oxygenic photosynthesis?
Answer:
In some organism oxygen is not evolved during photosynthesis and is called as Non oxygenic and Anaerobic Photosynthesis (NOAP).
Eg. Green sulphur, Purple sulphur, and green filamentous bacteria.

Samacheer Kalvi 11th Bio Botany Guide Chapter 13 Photosynthesis

Question 11.
Why do we call carotenoids as shield pigments.
Answer:

  • Carotenoids are yellow to orange pigments mostly tetraterpens and absorb light strongly in the blue to violet region of visible spectrum.
  • These pigments protect chlorophyll from photosynthetic oxidative damage.

Question 12.
Notes on xanthophylls.
Answer:

  • Yellow pigments like carotene but contain oxygen.
  • Lutein – responsible for colour change of leaves during autumn season.
  • Eg. Lutein, violaxanthin, & Fuco xanthin.

Question 13.
What are Quantosomes.
Answer:

  • They are physiological photosynthetic units, located on the inner membrane of thylakoid lamellae of size 180A X 160 A length & breadth.
  • It was named by Park &Pickins( 1964).
  • One quantosome contains about 230 chlorophyll molecules.
  • It constitutes a photosynthetic unit responsible for the production of one O2 moleucle or reduction of one C02 molecule.

Question 14.
What is Bioluminescence?
Answer:
It is the special aspect of few living organism, in which there are some bio chemical substances production is responsible for the emission of light by a living organism.

Samacheer Kalvi 11th Bio Botany Guide Chapter 13 Photosynthesis

Question 15.
What is meant by photolysis of water or photo oxidation of water.
Answer:

  • The splitting up of water molecule into OH’ ions and H+ ions.
  • The process of photolysis is associated with oxygen Evolving complex (OEC or water splitting complex in pigment system II.
  • It is catalysed by Mn++and Cl ions.
  • At the end of Photolysis 4H+, 4e and O2  are evolved from water.

Question 16.
Explain water oxidizing clock or S state mechanism.
Answer:

  • The splitting of water molecule, mechanism was studied by KoK et, al (1970).
  • It consists of a series of 5 states so, s1, s2, s3, s4.
  • Each sate acquires positive charge by a photon (hv) and after the state s4 – if acquires 4 positive charges 4 electron and evolution of oxygen.
  • Two molecules of water go back to the so.
    At the end of photolysis 4H+, 4e and O2 are evolved from water.
    4H2O → 4H++ + 40H
    40H–  → 2H20+02+4e
    2H2O → 4H++ + O2 + 4e.

Question 17.
Distinguish between photophosphorylation and oxidative phosphorylation.
Answer:

Photophosphorylation Phosphorylation
It is the process of synthesis of ATP from ADP by the addition of phosphate takes place with the help of during photosynthesis light generated electron, is known as photophosphorylation. It is of two types Cyclic and Non cyclic photophosphorylation. The process of production of ATP via terminal oxidation of reduced coenzymes during respiration is known as oxidative phosphorylation.

Question 18.
What is meant by ‘Z’ scheme.
Answer:
During Non cyclic photophosphorylation in the light reaction of Photosynthesis, the electron flow looks like the appearance of letter ‘Z’ and so known as Z – scheme.

Question 19.
What are the conditions for the occurrence of Non cyclic photophosphorylation.
Answer:

  • Non Cyclic Photo Phosphorylation occur, when.
  • There is availability of NADP+ for reduction.
  • Two molecules of water go back to the so.
  • When there is splitting of water molecules.
  • When both PSI and PS II are activated.

Samacheer Kalvi 11th Bio Botany Guide Chapter 13 Photosynthesis

Question 20.
Why do we consider Cyclic electron transport or PS I – considered to be formed earlier in evolution?
Answer:

  • P.S. I – need light of longer wave length (P – 700nm)
  • P. S. I – acts under low light intensity.
  • P.S.I- acts under low C02 concentration.
  • P.S.I – function even under anaerobic conditions.
  • These are the aspects helps to consider PSI as an earlier formed one in evolution.

Question 21.
What are the 2 phases of light reaction.
Answer:
Light reaction has 2 phases

  1. Photo oxidation phase
  2.  Photo chemical phase.

I) Photo oxidation phase (POP):

  •  Absorption of light energy.
  • Transfer of energy from accessory pigments to reaction centre.
  • Activation of chlorophyll ‘a’ -molecule.

II) Photochemical phase (PCO):

  • Photolysis of water and evolution of oxygen.
  • Electron transport and synthesis of assimilatory power.

Question 22.
Green light induces lowest rate of photosynthesis justify.
Answer:

  • Yes green light induces lowest rate of photosynthesis because it is not coming under photosynthetically
  • Active reduction – (400 – 700 nm) known as PAR.
  • PAR – (Photosynthetic rate is maximum in blue and red light not in green Light.

Question 23.
What will be the quanta requirement for complete light reaction which releases 6 oxygen molecules?
Answer:

  • Complet light reaction releases 6 oxygen molecules.
  • If one molecule of oxygen evolution requires 8 quanta means for 6 oxygen molecules 6×8=48 quanta of light reaquired for complete light reaction.

Samacheer Kalvi 11th Bio Botany Guide Chapter 13 Photosynthesis

Question 24.
Give the balance sheet of Calvin or C3 cycle.
Answer:
One molecule C02 is fixed in one turn of calvin or C3 cycle.
So 6 turns of cycle will be required to fix 6 molecules of C02 – (i.e) to form one molecule of Glucose
C6H2O6

In Out
6C02 1 Glucose
18 ATP 18 ADP
12 NADPH 12 NADP

3 Mark Questions

IV.

Question 1.
Hydrogen energy is the future hope of the world – justify.
Answer:

  • Yes – Hydrogen stands a part as a promising alternative energy source.
  • Hydrogen is a component of water. There is more than enough water on earth to supply a global hydrogen fuel system.
  • Hydrogen is the highest energy content of any common fuel by weight.
  • It is a clean energy as there is no carbon emission produced directly during this cycle.

Uses :

  • To run vehicles, to heat homes office, to produce electricity, fuel air craft, etc. Thus it is a part of world’s energy future.

Samacheer Kalvi 11th Bio Botany Guide Chapter 13 Photosynthesis

Question 2.
What are the properties of light.
Answer:

  • Light is a transverse electromagnetic wave.
  • It consists of ocillating electric and magnetic fields that are perpendicular to each other and perpenticular to the direction of propagation of the light.
  • Light moves at a speed of 3 x 108 ms-1
  • Wave length is the distance between successive crests of the wave.
  • Light as a particle is called photon. Each photon contains an amount of energy known as quantum.
  • The energy of a photon depends on the frequency of the light.

Question 3.
Distinguish between Absorption spectrum & Action Spectrum.
Answer:

Absorption spectrum Action spectrum
A curve obtained by plotting the amount of absorption of different wave lengths of light by a pigment is called Absorption spectrum. The curve showing the rate of photosynthesis at different wavelengths of light is called action spectrum.

Question 4.
Distinguish between fluroescence and phosphorescence.
Answer:

Fluroescence Phosphorescence
Immediate emission of absorbed radiations in the form of radiation energy (light) in the red region. This is the delayed emission of absorbed radiations in the form of light in red region.
The electrons move from S1 →SO The electrons path way is from S2 →S1 →T1→ SO

Question 5.
What are the 3 excited states of Chlorophyll.
Answer:
When a photon of light collides with the chlorophyll molecule, an electron from outer most orbit is moved to higher energy orbit causing excitation of chlorophyll. ‘

  1. First singlet state (S1)
  2. Second singlet state (S2)
  3.  First triplet state (T1)

Question 6.
Write down the significance of Photosynthesis.
Answer:

  • Photosynthetic organisms provide food for all living organisms on earth either directly or indirectly All other organism depend on them for energy.
  • It liberates oxygen in the atmosphere and balances.
  • Fuels such as coal, petroleum, and other fossil fuels are preserved forms got only from photosynthetic plants.
  • It also provides fodder, fibre, fire wood, timber useful medcinial prodcuts and these sources come by the act of photosynthesis.

Samacheer Kalvi 11th Bio Botany Guide Chapter 13 Photosynthesis

Question 7.
What is DCMU?
Answer:

  • It is a chemical herbicide having inhibiting effect on photosynthesis.
  • It is Dichloro phenyl Dj Methyl Urea.
  • It can inhibit electron flow during light reaction of photosynthesis.
  • It is a herbicide that blocks the plasto quinone binding site of P.S II and inhibit electron flow from plasto quinone to cytochrome.

Question 8.
State black man’s law of limiting factor.
Answer:
It is a modified law proposed by Liebig’s law of minimum.

Definition:
According to Blackmann at any given point of time, the lowest factor among essentials will limit the rate of Photosynthesis.

Example:
When in a condition, if light intensity is low also C02 concentration i low, in this situation among the two factors which ever is the lowest is considered as the limiting factor here among the essentials CO2 concentration is the limiting factor.

Samacheer Kalvi 11th Bio Botany Guide Chapter 13 Photosynthesis

Question 9.
Notes on RUBISCO.
Answer:

  • RUBISCO is known as RUBP carboxylase oxygenase enzyme.
  • This is the most abundant protein found on earth.
  • It constitutes 16% of the chioroplast protein.
  • It act as carboxvlase in the presence of CO2
  • It act as oxygenase in the absence of CO2

Question 10.
State some interesting facts about C4 cycle.
Answer:

  • C4 cycle is an alternative path way for CO2 fixation.
  • It occur in nearly 1000 plant species 300 dicots but mostly 700 monocots (tropical and sub tropical grasses)
  • It represent about 5% earths biomass and 1% of its known plants
  • 30% terrestrial carbon fixation on earth is due to C4 So, if C4 plants on earth is increased, then by carbon sequestration by thus strategy severe climate change would be avoided in the near future.

Samacheer Kalvi 11th Bio Botany Guide Chapter 13 Photosynthesis

Question 11.
What is Kranz Anatomy or what is meant by Dimorphism of Chloropiasts in C4 plants.
Answer:

C3 plants C4 plants
C3 plants kranz Anatomy not seen C4 plants plants show kranz Anatomy
C3 plants only one type of chloropiasts seen both in bundle sheath and mesophyll cells. C4 plants Bundle sheath surrounding the vascular bundles have larger chloroplast and have thylakoids are free, not arranged in granum.
Thylakoids are arranged in granum as coins. Mesophyll cells have smaller chloropiasts thylakoid arranged in granum

Question 12.
Write clown the significance of CAM cycle.
Answer:

  • It is advantageous for succulent plants to obtain CO2, from malic acid when stomata are closed.
  • During day time stomata are closed and CO2 is not taken in but continue their photosynthesis.
  • Stomata are closed during day & help plants to avoid transpiration and water loss.

Question 13.
Compare the C3 and C4 on the basis of ATP production.
Answer:

C3 plants C4 plants
The evolution of one oxygen molecule (4 electrons required) requires 8 quanta of light
C3 plants utilise 2 ATPs and 2 NAD PH+H+ to evolve one oxygen molecule C4 plants utilise 5 ATPs and 2NADPH + H+ to evolve one oxygen molecule
To evolve 6 molecules of oxygen or 1 molecule of Glucose 8 ATPs and 12 NADPH + H+ are utilised. To evolve 6 molecules of oxygen 30 ATPs and 12 NADPH + H+ are utilised.

Question 14.
What will be the quanta requirement for complete light reaction which releases 6 oxygen molecules?
Answer:
Complete light reaction releases 6 oxygen molecules if one molecule of oxygen evolution, requires 81 quanta means for 6 oxygen molecules 6 x 8 = 48 quanta of light required for complete light reaction.

Question 15.
Draw the Graphical representation of any 3 factors affecting photosynthesis.
Answer:
Samacheer Kalvi 11th Bio Botany Guide Chapter 13 Photosynthesis 7

1. Light Intensity
2. CO2 Concentration
3. Temperature

Samacheer Kalvi 11th Bio Botany Guide Chapter 13 Photosynthesis

5 Mark Questions

V.

Question 1.
Describe the structure of chloropiast.
Answer:
Chloropiast are the sites of photosynthesis.
Structure:

  • Double membrane bound organelle.
  • Discoid or lens shaped.
  • 4-10 um in diameter, 1.33 um thickness.
  • The space between the membranes is 100 – 200 A.

Stroma:

  • Proteinaceous matrix –
  • A sac like membranous system called thylakoid or lamellae is present in stroma.
  • Thylakoids are stacked  like coin – known as granum. (grana – plural).
  • In each chloropiast 40 – 80 grana and each grana consists of 5 to 30 thylakoids.
  • The thylakoids are known as grana lamellae and the lamellae in the stroma is known as stroma lamellae.
  • A thinner lamella known as fret membrane connects grana.
  • Disc size of thylakoid is 0.25 to 0.8 micron in diameter.
  • Pigment system I is located on outer thylakoid membrane.
  • Pigement system II is located on inner membrane facing thylakoid lumen.
  • Grana lamellae have both PS I & PS II.
  • Stroma lamellae have only PS I
  • Chloropiast contains 30 – 35% proteins, 20 – 30% phopholipids, 5 -10% chlorophylls, 4 – 5% carotenoids.
  • It also contain 70s Ribosome, Circular DNA, Starch grain.
  • Inner membrane consists of spherical structures called Quantasomes.
  • Stroma – contain photosynthetic enzyme.

Question 2.
Structure of Chloropiast.
Answer:
Samacheer Kalvi 11th Bio Botany Guide Chapter 13 Photosynthesis 8

Question 3.
Notes on photosystem and Reaction centre.
Answer:

  • Thylakoid membrane contains photosystem I (PSI) and photosystem II (PSII)
  • PS I is unstacked region ofgranum tàcing ctroma ofchÍoroplast.
  • PS II is found in stacked region ofthyakoid membrane facing lumeti of thylakoid.
  • Each photosystem consists of central core complex (CC) and light harvesting complex (LHC) or Antenna molecules.
  • The core complex consists of respective reaction centre associated with proteins, electron donors and acceptors.
  • PSI – CCI consists of reaction centre P 700 and LHC – I
  • PS II- CC II consists of reaction centre P680 and LHC – II
  • Light harvesting complex consists of several chiorophylls, carotenoids and xanthophyll molecules.
  • The main function of LHC is to harvesting light energy and transfer it to their respective reaction centre.

Samacheer Kalvi 11th Bio Botany Guide Chapter 13 Photosynthesis

Question 4.
Difference between photosystem I and Photosystem II.
Answer:

Photosystem I Photosystem II
1. The reaction centre is P700 1. Reaction centre is P 680.
2. PSI is involved in Photolysis of water and evolution. 2. PS II participates in Non – Cyclic pathway
3. Not involved in photolysis of water and evolution of oxygen. 3. Photolysis of water and evolution of oxygen take place.
4. It receives electrons from PSII during non – cyclic photophosphorylation. 4. It receives electrons by photolysis of water.
5. Located in unstacked region granum racing chloroplast stroma. 5. Located in stacked region of thylakoid membrane facing lumen of thylakoid.
6. Chlorophyll and carotenoid ratio is 20 to 30:1 6. Chlorophyll and carotenoid ratio is 3 to 7:1

Question 5.
Differences between Cyclic Photophosphorylation and Non – cyclic photophosphorylation.
Answer:

Cyclic Photophosphorylation Non – Cyclic Photophosphorylation
1. PSI only involved 1. PSI and PS II involved.
2. Reaction centre is P 700 2. Reaction centre is P 680.
3. Electrons released are cycled back 3. Electron released are not cycled back.
4. Photolysis of water does not take place 4. Photolysis of water takes place
5. Only ATP Synthesized 5. ATP and NADPH + H+ are synthesized.
6. Phosphorylation takes place at two places 6. Phosphorylation takes place at only one place
7. It does not require an external electron donor. 7. Requires external electron donor like H20 or H2S
8. It is not sensitive to dichloro dimethyl urea (DCMU) 8. It is sensitive to DCMU and inhibits electron flow

Question 6.
Explain chemiosmotic theory.
Answer:

  • Proposed by Mitchell in 1966.
  • It explains the formation of ATP molecules in photosynthesis & Respiration.
  • ATP synthesis in photosynthesis is linked to development of proton gradient across thylakoid membrane
  • Development of Proton gradient:
  • Splitting of water molecules takes place on the inner side of thylakoid membrane. The protons produced are accumulated in thylakoid lumen.
  • With the transport of electrons through photosystems, protons are also transported across membrane.
  • The number of protons decreases in the stroma and increases in the lumen. Thus creates a proton gradient.
  • The proton gradient is broken due to the movement of proton across the membrane to the stroma through CFO of the ATP synthetase enzyme.
  • The proton motive force or chemical gradient of W ion across the membrane catalyses ATP generation.
  • This membrane of ATP formation known as cherniosmotie mechanism of ATP formation.
  • The proton gradient is broken due to the movement of proton across the membrane to the stroma through CFO of the ATP synthetase enzyme.
  • The proton motive force or chemical gradient of H+ ion across the membrane catalyses ATP generation.
  • This membrane of ATP formation known as chemiosmotie mechanism of ATP formation.

Samacheer Kalvi 11th Bio Botany Guide Chapter 13 Photosynthesis

Question 7.
Explain Non cyclic photophosphorylation.
Answer:

  • When PS II (P680) get activated, electrons from high energy state passes through a series of electron carriers like pheophytin, plastoquinone cytochrome complex, plastocyanin and finally accepted by PS I (P700). During this flow ATP is generated :
  • PS. I (P 700) is activated by light electrons moved to high energy state and accepted by electron acceptor (FRS) Ferredoxin Reducing Substance, during down hill passes through Ferredoxin. During this process NADPH is reduced by H+ formed during photolysis.
  • Electrons released from PS II are not cycled back but used in the reduction of NADPH+ into NADPH+H+.
  • During the electron transport it generates ATP and this type of Phophorylation is called.
    Non Cyclic Photophosphorylation:
  • The electron flow looks like the letter ‘Z’ so known as Z scheme. It has 3 stages.

I) Electron transport from water to P 680:
Electrons lost by the PS II are replaced by electrons from splitting of water molecule, producing electron, protons, and oxygen.

II) Electron transport from P680 to P 700 :
The flow, through various electron carrier molecules, like pheophytin, plastoquinone (PQ) cytochrome b6 – F complex, plastocyanin (PC) finally reaches P 700 (P.S.I)

III) Electron transport from P 700 to NADP+ PSI (P700) is excited now and the electrons pass through ferredoxin, NADP is reduced to NADPH + H+
Samacheer Kalvi 11th Bio Botany Guide Chapter 13 Photosynthesis 9

Question 8.
Explain Calvin cycle or C3 cycle?
Answer:

  • It follows light reaction.
  • Utilises ATP and NADPH + H+ produced during light reaction, and reduce carbon dioxide carbohydrate.
  • These reactions does not require light so named as Dark reaction.
  • The first formed product is a 3 carbon compound (Phospho Glyceric Acid) and so known as C3 cycle.
  • It was found by Melvin, Calvin, and Benson – so knownas Calvin cycle.
    Occur in the stroma of the chloroplast.
  • It is temperature dependent, and so it is also called thermo – chemical reaction.

Phase I carboxylation (Carbon fixation):

  • The 5 C compound Ribulose 1 – 5 Bis phosphate (RUBP) with the help of (RUBISCO) enzyme accepts one molecule of carbon dioxide -4 6 carbon compound (unstable)
  • The 6c compound is broken into → 2 molecules of 3 c compound.
  • Samacheer Kalvi 11th Bio Botany Guide Chapter 13 Photosynthesis 19

Phase II – Glycolytic Reversai/Reduction :
Samacheer Kalvi 11th Bio Botany Guide Chapter 13 Photosynthesis 10

Phase III – Regeneration :

  • The regeneration of RUBP involves several intermediate compounds of 6c, 5c, 4c and 7c compounds.
  • Fixation of one CO2 require 3 ATPs + 2NADPH4 + H+
  • Fixation of six CO2 require I 8 ATPs+  2NADPH + H+
  • 6 c compound is the net gain to form hexose sugar.Samacheer Kalvi 11th Bio Botany Guide Chapter 13 Photosynthesis 11

Samacheer Kalvi 11th Bio Botany Guide Chapter 13 Photosynthesis 12

Samacheer Kalvi 11th Bio Botany Guide Chapter 13 Photosynthesis 13

Question 9.
Draw the flow Chart of C4 path way?
Answer:
Samacheer Kalvi 11th Bio Botany Guide Chapter 13 Photosynthesis 14

Question 10.
Explain CAM Cycle?
Answer:

  • It is one of the carbon path ways in succulent plants growing in semi arid or xerophytic condition.
  • The stomata are closed during day (scoto active) and open during night.
  • This reverse rhythm help to conserve water loss through transpiration and will stop the fixation of CO2 during day.
  • At night time CAM plants fix CO, with help of (PEP) phospho Enol Pyruvic acid and produce (OAA) Oxalo Acetic Acid.
  • Subsequently OAA is converted into Malic acid like C4 cycle and get accumulated in the vacuole, increasing the acidity.
  • During day time stomata, are closed and Malic acid is decarboxylated in to pyruvic acid resulting in the decrease of acidity.
  • C02 thus, formed enter into Calvin cycle and produces carbohydrates.
    Samacheer Kalvi 11th Bio Botany Guide Chapter 13 Photosynthesis 15

Question 11.
Give the flow chart of Photo respiration or C2 cycle.
Answer:
Samacheer Kalvi 11th Bio Botany Guide Chapter 13 Photosynthesis 16

Question 12.
Differentiate Photorespiration and Dark respiration.
Answer:

Photorespiration Dark respiration
1. It takes place in photosynthetic green cells It takes place in all living cells
2. It takes place only in the presence of light It involves only Mitochondria
3. It involves Chloroplast, Peroxisome and Mitochondria It involves only Mitochondria
4. It does not involve Glycolysis, Kreb’s cycle and ETS It involves Glycolysis, Kreb’s cycle and ETS
5. Substrate is Glycolic acid Substrate is Carbohydrates protein or fats
6. It is not essential for survival Essential for survival
7. No phosphorylation and yield of ATP Phosphorylation produces ATP energy
8. NADH2 is oxidised to NAD+ NAD+ is reduced to NADH2
9. Hydrogen peroxide is produced Hydrogen peroxide is not produced
10. End products are CO2 and PGA End products are CO2 and water

Question 13.
Give any 5 External factors affecting photosynthesis.
Answer:

  1. Carbon dioxide
    330ppm or 0.3% of CO2 is available in the atomsphere If there is increase in CO2 concentration the rate of Photosynthesis increases -If it increases beyond 500 PPm rate of photosynthesis will be inhibited.
  2. Oxygen:
  • When there is increase in oxygen concentration there is unhibition of photosynthesis Warburg – studied this in chlorellain 1920.
  • This effect is known as Warburg effect.

3. Temperature:

  • Optimum temperature for photosynthesis vary from plant to plant
  • Normally it is 25°C to 3 5°C
  • In Opuntia it is 55°C
  • In Lichens it is 20°C
  • In Algae growing in hot spring it is 75°C
  • At high and low temperature the stomata will close also the enzymes get inactivated.

4. Water:

  • Pholysis of water provide electrons and protons for the reduction of NADP – directly.
  • Affect stomatal movement and hydration of protoplasm – indirectly.
  • During water stress, supply of NADPH + H+ affected

5. Minerals:

Deficiency Effect
Mg, Fe and N Synthesis of chlorophyll
P phosphorylation reactions
Mn, Cl- photolysis of water
CU Formation of plastocyanin

Samacheer Kalvi 11th Bio Botany Guide Chapter 13 Photosynthesis

Question 14.
Explain test tube funnel experiment.
Answer:
AIM: To proove that oxygen is evolved during Photosynthesis.
Procedure:
Take some hydrilla plant and place them at the bottom of a beaker containing water – Add, little NaHCO3 in to the water. Cover plant with an inverted funnel Invert a test tube over the funnel keep this set up in sun light.

Observation: Air bubbles are released from Hydrilla plant and collected in the test tube by downward displace ment of water. Take the test tube carefully by closing with a finger and then introduce a burning match stick, it bum brightly.
Inference: Hydrilla plant perform photosynthesis and oxygen is liberated during photosynthesis.
Samacheer Kalvi 11th Bio Botany Guide Chapter 13 Photosynthesis 17

Question 15.
Explain the experiment to determine rate of photosynthesis by Witmott’s bubbler.
Answer:
Procedure:

  • Wilmott’s bubbler consists of a wide mouth bottle fitted with a single holed cork, a glass tube with lower and having wider opening to insert hydrilla plant.
  • The upper end is fitted to a narrow bottle with water.
  • Fill the bottle with water and insert hydrilla living into wider part of the tube.
  • Hydrilla plant should be cut inside the water to avoid entry of
    air bubbles.
  • Fix the tube with jar which acts as water reservoir.
  • Keep the apparatus in sunlight count the bubbles when they are in same size.
    Samacheer Kalvi 11th Bio Botany Guide Chapter 13 Photosynthesis 18

Question 16.
Differentiate photosynthesis in plants and Bacterial photosynthesis.
Answer:

Photosynthesis Bacterial photosynthesis
1. Cyclic and Non – Cyclic phosphorylation takes place Only cyclic phosphorylation takes place
2. Photosystem I and II involved Photosystem I only involved
3.  Electron donor is water Electron donor is H9S
4.  Oxygen is evolved Oxygen is not evolved
5. Reaction centres are P700 and P680 Reaction centre is P890
6.  Reducing agent is NADPH + H+ Reducing agent is NADH + H+
7. PAR is 400 to 700 nm PAR is above 700nm
8.  Chlorophyll, Carotenoid and Xanthophyll Bacterio chlorophyll and Bacterio viridin
9. Photosynthetic apparatus – chloroplast It is chromosomes and Chromatophores

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