Photosynthesis in Higher Plants NEET PYQs (2005–2026) with Solutions

10 solved Photosynthesis in Higher Plants PYQs

Real NEET and AIPMT questions from this chapter, newest first. Try each one, then open the answer and the step-by-step explanation.

1. Question 1 (NEET 2026)

   NEET 2026EasyPhotorespiration and RuBisCO oxygenation

   Photorespiration reaction catalyzed by RuBisCo is shown below: $\mathrm{RuBP} + \mathrm{O_2} \rightarrow$ 3-Phosphoglycerate + X. Identify “X” from the given options:

   1. AOption A: Phosphoenolpyruvate
   2. BOption B: 2-Phosphoglycolate
   3. COption C: Oxaloacetate
   4. DOption D: Malate

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   Correct answer: (B) 2-Phosphoglycolate

   Explanation

   In photorespiration RuBisCO acts as an oxygenase. Instead of adding $\mathrm{CO_2}$, it binds $\mathrm{O_2}$ to RuBP: $$\mathrm{RuBP} + \mathrm{O_2} \rightarrow \text{Phosphoglycerate} + \text{Phosphoglycolate}$$ So one molecule of 3-phosphoglycerate and one molecule of 2-phosphoglycolate are formed, and X is 2-phosphoglycolate. Phosphoenolpyruvate is the primary $\mathrm{CO_2}$acceptor in$\mathrm{C_4}$plants, and oxaloacetate and malate are$\mathrm{C_4}$ acids of the Hatch and Slack pathway. Hence the answer is option (B).

2. Question 2 (NEET 2026)

   NEET 2026EasyPhotosystems and reaction centre P700

   Which pigment has absorption peak at 700 nm in the photosynthetic reaction centre PS I (P700)?

   1. AOption A: Chlorophyll b
   2. BOption B: Chlorophyll a
   3. COption C: Xanthophylls
   4. DOption D: Carotenoids

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   Correct answer: (B) Chlorophyll a

   Explanation

   Each photosystem has all pigments except one molecule of chlorophyll a forming a light-harvesting complex (antenna). The reaction centre itself is a single chlorophyll a molecule. In PS I the reaction centre chlorophyll a has an absorption peak at 700 nm and is called P700; in PS II it absorbs at 680 nm and is called P680. Chlorophyll b, xanthophylls and carotenoids are accessory pigments of the antenna. So the answer is option (B).

3. Question 3 (NEET 2026)

   NEET 2026MediumRespiration in Plants - Respiratory Quotient (RQ)

   2(C₅₁H₉₈C₆) + 145 O₂ → 102 CO₂ + 98 H₂O + energy The Respiratory Quotient (RQ) of a biomolecule used for respiration, as per the above equation would be:

   1. AOption A: Between 0.5 and 0.95
   2. BOption B: Less than 0.5
   3. COption C: 1.0
   4. DOption D: Between 1.25 and 2

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   Correct answer: (A) Between 0.5 and 0.95

   Explanation

   Respiratory Quotient (RQ) = Volume of CO₂ evolved / Volume of O₂ consumed. For the given reaction: RQ = 102/145 = 0.70 Since 0.70 lies between 0.5 and 0.95, option (A) is correct. Such RQ values are characteristic of fats.

4. Question 4 (NEET 2026)

   NEET 2026MediumC3 and C4 Pathways, Photorespiration and Chemiosmosis

   Find the incorrect statement(s) about photosynthesis from the following: A. The water splitting complex is associated with PS I. B. C$_4$ plants use the C$_3$ pathway of CO$_2$ fixation as the main biosynthetic pathway. C. In C$_4$ plants, photorespiration does not occur. D. C$_3$ plants exhibit 'Kranz' anatomy. E. ATP synthesis in chloroplast occurs through chemiosmosis. Choose the answer from the options given below:

   1. AOption A: B and C only
   2. BOption B: B only
   3. COption C: B and E only
   4. DOption D: A and D only

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   Correct answer: (D) A and D only

   Explanation

   The water splitting complex is associated with PS II, not PS I, making statement A incorrect. Kranz anatomy is found in C4 plants, not C3 plants, making statement D incorrect. Statements B, C and E are correct.

5. Question 5 (NEET 2026)

   NEET 2026MediumEarly experiments on photosynthesis

   Select the correct sequence of experiments that led to a gradual understanding of photosynthesis in green plants.

   1. AOption A: Absorption spectra of chlorophyll a and b $\rightarrow$ production of glucose $\rightarrow$ release of oxygen $\rightarrow$ role of air
   2. BOption B: Role of air $\rightarrow$ release of oxygen $\rightarrow$ production of glucose $\rightarrow$ absorption spectra of chlorophyll a and b
   3. COption C: Release of oxygen $\rightarrow$ production of glucose $\rightarrow$ absorption spectra of chlorophyll a and b $\rightarrow$ role of air
   4. DOption D: Production of glucose $\rightarrow$ role of air $\rightarrow$ release of oxygen $\rightarrow$ absorption spectra of chlorophyll a and b

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   Correct answer: (B) Role of air $\rightarrow$ release of oxygen $\rightarrow$ production of glucose $\rightarrow$ absorption spectra of chlorophyll a and b

   Explanation

   The historical sequence described in NCERT is: 1. Joseph Priestley (1770) showed, with a candle and a mouse in bell jars with a mint plant, that air plays an essential role (plants restore the air) — role of air. 2. Jan Ingenhousz showed that sunlight is essential and that green parts of the plant release oxygen (bubbles around green parts in light) — release of oxygen. 3. Julius von Sachs (1854) showed that green plants produce glucose, usually stored as starch — production of glucose. 4. T.W. Engelmann, using a prism and aerobic bacteria with Cladophora, obtained the first action spectrum, which roughly resembles the absorption spectra of chlorophyll a and b. So the order is role of air → release of oxygen → production of glucose → absorption spectra of chlorophyll a and b, which is option (B).

6. Question 6 (NEET 2026)

   NEET 2026EasyCarbon Fixation and Calvin Cycle

   The enzyme required for carboxylation in the Calvin cycle is

   1. AOption A: Hexokinase
   2. BOption B: PEP carboxylase
   3. COption C: RuBP carboxylase-oxygenase
   4. DOption D: Carboxypeptidase

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   Correct answer: (C) RuBP carboxylase-oxygenase

   Explanation

   RuBisCO (RuBP carboxylase-oxygenase) catalyses the carboxylation of RuBP during the Calvin cycle.

7. Question 7 (NEET 2026)

   NEET 2026EasyCalvin cycle: turns per glucose

   How many turns of Calvin cycle are required for the formation of three molecules of glucose?

   1. AOption A: 6
   2. BOption B: 3
   3. COption C: 1
   4. DOption D: 18

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   Correct answer: (D) 18

   Explanation

   Each turn of the Calvin cycle fixes one molecule of $\mathrm{CO_2}$. A glucose molecule has 6 carbon atoms, so 6 turns of the cycle are needed to make one glucose molecule. For three molecules of glucose: $$3 \times 6 = 18 \text{ turns}$$ Hence the answer is option (D).

8. Question 8 (NEET 2026)

   NEET 2026MediumPhotorespiration in C3 plants

   Which of the following statements regarding photorespiration are correct? (a) Do not occur in $\mathrm{C_3}$ plants (b) $\mathrm{CO_2}$ is consumed and $\mathrm{O_2}$ is generated (c) Phosphoglycolate is formed (d) No synthesis of ATP and NADPH Choose the correct answer from the options given below:

   1. AOption A: (a) and (d) only
   2. BOption B: (c) and (d) only
   3. COption C: (b) and (d) only
   4. DOption D: (a) and (b) only

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   Correct answer: (B) (c) and (d) only

   Explanation

   (a) False: photorespiration occurs in $\mathrm{C_3}$ plants; it is $\mathrm{C_4}$ plants in which it does not occur, because they concentrate $\mathrm{CO_2}$ around RuBisCO. (b) False: in photorespiration $\mathrm{O_2}$ is taken up (RuBisCO acts as oxygenase) and $\mathrm{CO_2}$ is released. (c) True: $\mathrm{RuBP} + \mathrm{O_2} \rightarrow$ phosphoglycerate + phosphoglycolate. (d) True: in the photorespiratory pathway there is neither synthesis of sugars nor of ATP (or NADPH); instead ATP is used up, making it a wasteful process. So (c) and (d) are correct, which is option (B).

9. Question 9 (NEET 2025)

   NEET 2025EasyPhotosynthetic Pigments

   Match List I with List II : Choose the option with all correct matches.

   1. AOption A: A-III, B-IV, C-II, D-I
   2. BOption B: A-III, B-I, C-II, D-IV
   3. COption C: A-I, B-II, C-IV, D-III
   4. DOption D: A-I, B-IV, C-III, D-II

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   Correct answer: (B) A-III, B-I, C-II, D-IV

   Explanation

   Chlorophyll a is blue-green, chlorophyll b is yellow-green, xanthophylls are yellow pigments, and carotenoids are yellow to yellow-orange pigments.

10. Question 10 (NEET 2024)

    NEET 2024EasyGrowth and Development

    Formation of interfascicular cambium from fully developed parenchyma cells is an example for

    1. AOption A: Dedifferentiation
    2. BOption B: Maturation
    3. COption C: Differentiation
    4. DOption D: Redifferentiation

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    Correct answer: (A) Dedifferentiation

    Explanation

    Dedifferentiation is the process in which mature cells regain the capacity to divide, as seen in the formation of interfascicular cambium.