PYQ NEET MCQ Chapter 13: Photosynthesis in Higher Plants

This chapter discusses the most interesting biochemical process in our ecosystem called photosynthesis. Autotrophs use this reaction to convert light energy from the sun to chemical energy. It is this energy that forms the backbone of the complete ecosystem and food web. We first discuss discoveries made by various scientists in photosynthesis. Then we understand all the pigments that autotrophs have for photosynthesis followed by light and dark reactions. In the end, we discuss photorespiration and factors that affect photosynthesis. Let’s have a look at Photosynthesis NEET Previous Year Questions. 

ATTEMPT ALL QUESTIONS BY YOURSELF FIRST THEN CHECK THE SOLUTIONS. BRIEF EXPLANATIONS ABOUT THE SOLUTIONS ARE GIVEN AT THE END AS WELL.

Photosynthesis NEET Previous Year Questions

Questions from 2021

1. The first stable product of CO₂ fixation in sorghum is : (2021)

(a) Succinic acid

(b) Phosphoglyceric acid 

(c) Pyruvic acid 

(d) Oxaloacetic acid

2. Which of the following statements is incorrect? (2021)

(a) Grana lamellae have both PSI and PS II.

(b) Cyclic photophosphorylation involves both PSI and PS II.

(c) Both ATP and NADPH + H+ are synthesised during non-cyclic photophosphorylation

(d) Stroma lamellae have PS I only and lack NADP reductase.

Questions from 2020

3. In light reaction, plastoquinone facilitates the transfer of electrons from : (2020)

(a) Cyt B6f complex to PS-I

(b) PS-I to NADP+

(c) PS-I to ATP synthase

(d) PS-II to Cyt B6f complex

4. The oxygenation activity of RuBisCo enzyme in photorespiration leads to the formation of (2020)

(a) 1 molecule of a 3-C compound

(b) 1 molecule of a 6-C compound

(c) 1 molecule of a 4-C compound and 1 molecule of a 2-C compound 

(d) 2 molecules of a 3-C compound

Questions from 2019

5. One scientist cultured Cladophora in a suspension of Azotobacter and illuminated the culture by splitting light through a prism. He observed that bacteria accumulated mainly in the region of (Odisha NEET 2019)

(a) Violet and green light 

(b) Indigo and green light

(c) Orange and yellow light 

(d) Blue and red light

Questions from 2018

6. Oxygen is not produced during photosynthesis by (2018)

(a) Green sulphur bacteria 

(b) Nostoc

(c) Cycas

(d) Chara.

7. Which of the following is not a product of the light reaction of photosynthesis? (2018)

(a) ATP

(b) NADH

(c) NADPH

(d) Oxygen

Questions from 2017

8. With reference to factors affecting the rate of photosynthesis, which of the following statements is not correct? (2017)

(a) Increasing atmospheric CO₂ concentration up to 0.05% can enhance CO₂ fixation rate.

(b) C3 plants respond to higher temperatures with enhanced photosynthesis while C4 plants have much lower temperature optimum.

(c) Tomato is a greenhouse crop that can be grown in a CO₂-enriched atmosphere for higher yield.

(d) Light saturation for CO₂ fixation occurs at 10% of full sunlight.

9. Phosphoenolpyruvate (PEP) is the primary CO₂ acceptor in (2017)

(a) C4 plants

(b) C2 Plants

(c) C3 and C4 plants

(d) C3 plants.

Questions from 2016

10. The process which makes a major difference between C3 and C4 plants is (2016)

(a) glycolysis

(b) Calvin cycle

(c) photorespiration

(d) respiration.

11. Water vapour comes out from the plant leaf through the stomatal opening. Through the same stomatal opening, carbon dioxide diffuses into the plant during photosynthesis. Reason out the above statements using one of the following options. (2016)

(a) The above processes happen only during nighttime.

(b) One process occurs during daytime and the other at night.

(c) Both processes cannot happen simultaneously.

(d) Both processes can happen together because the diffusion coefficient of water and CO₂ is different.

12. In a chloroplast, the highest number of protons are found in (2016)

(a) intermembrane space

(b) antennae complex

(c) stroma

(d) the lumen of thylakoids.

13. Emerson’s enhancement effect and Red drop have been instrumental in the discovery of (2016)

(a) photophosphorylation and cyclic electron transport

(b) oxidative phosphorylation

(c) photophosphorylation and non-cyclic electron transport

(d) two photosystems operating simultaneously.

14. A plant in your garden avoids photorespiratory losses, has improved water use efficiency, shows high rates of photosynthesis at high temperatures and has improved efficiency of nitrogen utilisation. In which of the following physiological groups would you assign this plant? (2016)

(a) CAM

(b) Nitrogen fixer

(c) C3

(d) C4

15. Water-soluble pigments found in plant cell vacuoles are (2016)

(a) carotenoids

(b) anthocyanins

(c) xanthophylls

(d) chlorophylls.

Questions from 2015

16. In photosynthesis, the light-independent reactions take place at (2015)

(a) photosystem II

(b) stromal matrix

(c) thylakoid lumen

(d) photosystem I.

17. Chromatophores take part in (2015)

(a) movement

(b) respiration

(c) photosynthesis

(d) growth.

More questions from 2019

18. A plant is exposed to very bright light. What is correct in this environmental condition? (2019)

(a) The accessory pigments promote light absorption.

(b) Chlorophylls are subjected to photo-oxidation.

(c) Accessory pigments absorb less light and transfer to chl a.

(d) Chlorophylls absorb light and transfer to accessory pigments.

19. Assertion: O2 is liberated in the non-cyclic photophosphorylation.

 Reason: The liberation of oxygen is due to the photolysis of water. (2019)

(a) Both assertion and reason are true and the reason is the correct explanation of assertion.

(b) Both assertion and reason are true but the reason is not the correct explanation of assertion.

(c) Assertion is true but the reason is false.

(d) Both assertion and reason are false.

20. Assertion: In the C3 cycle, the first stable compound is the 3C compound.

Reason: In C4 plants Calvin cycle is absent. (2019)

(a) Both assertion and reason are true and reason is the correct explanation of assertion.

(b) Both assertion and reason are true but reason is not the correct explanation of assertion.

(c) Assertion is true but reason is false.

(d) Both assertion and reason are false.

Solutions of Photosynthesis NEET Previous Year Questions

1. D
2. B
3. D
4. A
5. D
6. A
7. B
8. B
9. A
10. C
11. D
12. D
13. D
14. D
15. B
16. B
17. C
18. B
19. A
20. C

Short Explanation of Solutions 

1. The answer is part D because Sorghum is a C4 plant and in C4 plants Phosphoenol Pyruvate reacts with carbon dioxide to form OAA i.e. Oxaloacetic Acid (4 carbon compound ).
2. The answer is part B because Cyclic Phosphorylation involves only the PS1 complex. If both PS1 and PS2 complexes are involved then non-cyclic phosphorylation takes place.
3. The answer is part D because during non-cyclic photophosphorylation, light energy excites electrons from the PSII chlorophyll complex and the first electron acceptor is plastoquinone. Plastoquinone further transfers this electron to the Cytochrome B6f complex.
4. Part A is the answer because the oxygenation activity of the RuBisCo enzyme in photorespiration leads to the formation of one molecule of 3-phosphoglyceric acid (3-C compound) and one molecule of phosphoglycolate (2-C compound).
5. The correct option is part D since the maximum rate of photosynthesis takes place in the red and blue wavelength of visible light. We observed that Cladophora, photosynthetic algae, had maximum accumulation in these light wavelength regions only.
6. The correct answer is A because Green Sulphur Bacteria uses Sulphur in place of oxygen for photosynthesis and produces H2S and not water/ H2O.
7. NADH is not produced in light reaction and it is produced during respiration. ATP and NADPH are produced in phosphorylation and oxygen are produced by splitting of water in light reaction. Hence, part B is the answer.
8. C3 have a low-temperature optimum ( 25-30 celsius) and show photorespiration whereas C4 plants have a high-temperature optimum (30-40 celsius) and have enhanced photosynthesis because it does not show photosynthesis. Thus, part B is the answer.
9. The correct option is part A because PhosphoenolPyruvate / PEP is a 3 Carbon compound that in presence of PEPcase fixes CO2 to form OAA i.e. Oxaloacetic Acid which is a 4 carbon compound and the first stable compound of the C4 cycle. Hence PEP is the primary CO2 acceptor in C4 plants.
10. The correct answer is the C part because C4 plants due to the C4 cycle can avoid the wasteful process of photorespiration, unlike C3 plants.
11. Water and carbon dioxide moves through stomatal openings depending upon the diffusion coefficient. CO2 diffusion is essential for photosynthesis as the fixation of CO2 starts the various cycles and water vapour moves out through the stomatal opening for transpiration. Both these processes can happen simultaneously. Thus, to conclude, D is the correct answer.
12. Proton pumps present on the thylakoid membrane transport protons to the lumen of the thylakoid from the stroma. This is done to produce ATP when the plants move protons out of the lumen. To summarize, part D is the correct option.
13. Emerson showed that when plants were exposed to monochromatic light the rate of photosynthesis was less; however, when multiple wavelength light was given, the rate of photosynthesis increased because both photosystems PSI and PSII started operating simultaneously. Thus, part D is correct.
14. C4 plants because of the C4 cycle can avoid the wasteful process of photorespiration and hence have increased efficiency. They have improved water use efficiency and rate of photosynthesis. Therefore, part D is the answer.
15. The correct answer is part B because anthocyanin is water-soluble whereas Carotenoids, xanthophylls and chlorophylls are fat-soluble.
16. The accurate answer is part B because the light reaction involves PSII as well as PSI and it takes place in the thylakoid. Dark reaction / light-independent reaction takes place in the Stroma matrix of the chloroplast.
17. Since prokaryotes do not have chlorophylls, they have chromatophores that help them in photosynthesis, thus, part C is the correct option.
18. Chlorophylls are pigments that absorb light energy and release electrons to start a light reaction in higher plants. If the light energy that falls on a plant is very bright it means the electromagnetic waves have very high energy. Hence photooxidation ( degradation of the compound) of chlorophylls can occur. Thus, part B is the correct option.
19. Oxygen is liberated by the splitting of water in noncyclic photophosphorylation to give electrons to the PSII complex.
20. The Calvin Cycle is universal and takes place in all the plants. C3 plants have a C3 cycle and as the name indicates this cycle has the first stable compound 3-phosphoglycerate, a 3 carbon compound.

Thank you for reading.

Team MBD

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