CBSE Class 11 Biology – Photosynthesis in Higher Plants | MCQs with Answers & Explanations (NCERT Based)

Course & Examination Details

Course: CBSE Class 11 Biology
Unit: Unit IV – Plant Physiology
Chapter: Chapter 13 – Photosynthesis in Higher Plants
Prescribed Textbook: NCERT
Board: CBSE

CBSE Board Examination Relevance

• MCQs assess conceptual clarity, application, and NCERT terminology
• Frequently included in unit tests, internal assessments, and annual exams
• All questions follow NCERT definitions, processes, and explanations

Section A: Light Reaction (MCQs 1–18)

Q1. Photosynthesis occurs mainly in which plant cell organelle?

A. Mitochondria
B. Ribosomes
C. Chloroplast
D. Nucleus

Correct Answer: C
Explanation: Chloroplasts contain chlorophyll and enzymes required for both light and dark reactions of photosynthesis.

Q2. Light reactions of photosynthesis occur in the:

A. Stroma
B. Thylakoid membrane
C. Inner membrane
D. Cytoplasm

Correct Answer: B
Explanation: Thylakoid membranes contain photosystems and electron carriers required for light reactions.

Q3. The primary photosynthetic pigment is:

A. Chlorophyll b
B. Carotene
C. Xanthophyll
D. Chlorophyll a

Correct Answer: D
Explanation: Chlorophyll a directly participates in photochemical reactions.

Q4. Reaction centre of Photosystem II is:

A. P700
B. P680
C. P600
D. P500

Correct Answer: B
Explanation: PS II absorbs light at wavelength 680 nm.

Q5. Photolysis of water occurs in:

A. Photosystem I
B. Photosystem II
C. Calvin cycle
D. Mitochondria

Correct Answer: B
Explanation: Water splitting occurs at PS II, releasing oxygen.

Q6. Oxygen evolved during photosynthesis comes from:

A. Carbon dioxide
B. Glucose
C. Water
D. Chlorophyll

Correct Answer: C
Explanation: Oxygen is released due to photolysis of water.

Q7. Which of the following is NOT produced during light reaction?

A. ATP
B. NADPH
C. Oxygen
D. Glucose

Correct Answer: D
Explanation: Glucose is produced during dark reactions.

Q8. Photophosphorylation refers to:

A. Formation of NADPH
B. Splitting of water
C. Synthesis of ATP using light
D. Carbon fixation

Correct Answer: C
Explanation: ATP synthesis using light energy is photophosphorylation.

Q9. Cyclic photophosphorylation involves:

A. Both PS I and PS II
B. Only PS II
C. Only PS I
D. No photosystem

Correct Answer: C
Explanation: Only PS I operates and produces ATP.

Q10. Non-cyclic photophosphorylation produces:

A. ATP only
B. NADPH only
C. ATP, NADPH, and oxygen
D. Oxygen only

Correct Answer: C
Explanation: Non-cyclic pathway produces all three.

Q11. NADP⁺ acts as:

A. Proton donor
B. Electron carrier
C. Enzyme
D. Pigment

Correct Answer: B
Explanation: NADP⁺ accepts electrons and forms NADPH.

Q12. ATP synthesis occurs due to:

A. Diffusion
B. Chemiosmosis
C. Osmosis
D. Active transport

Correct Answer: B
Explanation: Proton gradient drives ATP synthesis via chemiosmosis.

Q13. Accessory pigments are useful because they:

A. Produce oxygen
B. Absorb all light wavelengths
C. Transfer absorbed energy to chlorophyll a
D. Fix carbon dioxide

Correct Answer: C
Explanation: They broaden absorption spectrum.

Q14. Which pigment protects chlorophyll from photo-oxidation?

A. Chlorophyll a
B. Chlorophyll b
C. Carotenoids
D. Anthocyanin

Correct Answer: C
Explanation: Carotenoids protect against excess light.

Q15. Proton gradient is built up across:

A. Inner chloroplast membrane
B. Outer chloroplast membrane
C. Thylakoid membrane
D. Nuclear membrane

Correct Answer: C

Q16. ATP synthase is located in:

A. Stroma
B. Thylakoid membrane
C. Outer membrane
D. Cytoplasm

Correct Answer: B

Q17. Which factor stops non-cyclic photophosphorylation?

A. Lack of PS I
B. Lack of PS II
C. Lack of NADP⁺
D. Lack of chlorophyll

Correct Answer: C

Q18. Light reaction directly provides energy for:

A. Respiration
B. Photorespiration
C. Calvin cycle
D. Transpiration

Correct Answer: C

Section B: Dark Reaction / Calvin Cycle (MCQs 19–32)

Q19. Dark reaction occurs in the:

A. Grana
B. Thylakoids
C. Stroma
D. Cytoplasm

Correct Answer: C

Q20. Dark reaction is also called:

A. Photochemical phase
B. Biosynthetic phase
C. Respiratory phase
D. Oxidative phase

Correct Answer: B

Q21. Enzyme responsible for CO₂ fixation is:

A. PEP carboxylase
B. RuBisCO
C. ATP synthase
D. Nitrate reductase

Correct Answer: B

Q22. First stable product of Calvin cycle is:

A. Glucose
B. RuBP
C. OAA
D. 3-PGA

Correct Answer: D

Q23. RuBisCO shows which dual activity?

A. Kinase and phosphatase
B. Oxidase and reductase
C. Carboxylase and oxygenase
D. Ligase and hydrolase

Correct Answer: C

Q24. Reduction phase of Calvin cycle uses:

A. ATP only
B. NADPH only
C. ATP and NADPH
D. CO₂ only

Correct Answer: C

Q25. Regeneration of RuBP requires:

A. CO₂
B. ATP
C. NADPH
D. Oxygen

Correct Answer: B

Q26. Photorespiration results in:

A. Sugar synthesis
B. ATP production
C. Loss of fixed carbon
D. Increased efficiency

Correct Answer: C

Q27. Photorespiration occurs mainly in:

A. C₄ plants
B. CAM plants
C. C₃ plants
D. Algae

Correct Answer: C

Q28. One glucose molecule requires how many CO₂ molecules?

A. 2
B. 4
C. 6
D. 12

Correct Answer: C

Q29. Total ATP required to synthesize one glucose molecule is:

A. 12
B. 18
C. 24
D. 36

Correct Answer: B

Q30. Calvin cycle depends directly on:

A. Light
B. Oxygen
C. ATP and NADPH
D. Chlorophyll

Correct Answer: C

Q31. RuBisCO is inefficient because it:

A. Needs light
B. Has low CO₂ affinity
C. Works slowly
D. Needs oxygen

Correct Answer: B

Q32. Calvin cycle was discovered by:

A. Hatch and Slack
B. Blackman
C. Melvin Calvin
D. Priestley

Correct Answer: C

Section C: C₃ and C₄ Pathways (MCQs 33–42)

Q33. First stable product in C₃ plants is:

A. OAA
B. RuBP
C. 3-PGA
D. Glucose

Correct Answer: C

Q34. First stable product in C₄ plants is:

A. 3-PGA
B. OAA
C. RuBP
D. Glucose

Correct Answer: B

Q35. Initial CO₂ acceptor in C₄ plants is:

A. RuBP
B. PEP
C. PGA
D. OAA

Correct Answer: B

Q36. Enzyme involved in initial CO₂ fixation in C₄ plants is:

A. RuBisCO
B. ATP synthase
C. PEP carboxylase
D. Nitrogenase

Correct Answer: C

Q37. Kranz anatomy is seen in:

A. C₃ plants
B. C₄ plants
C. CAM plants
D. Aquatic plants

Correct Answer: B

Q38. Calvin cycle in C₄ plants occurs in:

A. Mesophyll cells
B. Guard cells
C. Bundle sheath cells
D. Epidermal cells

Correct Answer: C

Q39. Photorespiration is absent in C₄ plants because:

A. RuBisCO is absent
B. CO₂ concentration is high near RuBisCO
C. Oxygen is absent
D. Light reaction is absent

Correct Answer: B

Q40. Which plants are more efficient at high temperature?

A. C₃ plants
B. C₄ plants
C. CAM plants
D. Algae

Correct Answer: B

Q41. C₄ pathway requires:

A. Less ATP
B. Same ATP
C. More ATP
D. No ATP

Correct Answer: C

Q42. C₄ pathway is also called:

A. Calvin cycle
B. CAM pathway
C. Hatch and Slack pathway
D. Blackman pathway

Correct Answer: C

Section D: Factors Affecting Photosynthesis (MCQs 43–50)

Q43. Which factor usually limits photosynthesis under natural conditions?

A. Light
B. Temperature
C. CO₂
D. Water

Correct Answer: C

Q44. Most effective wavelengths for photosynthesis are:

A. Green and yellow
B. Red and blue
C. Infrared
D. Ultraviolet

Correct Answer: B

Q45. Optimum temperature for photosynthesis is:

A. 5–10°C
B. 15–20°C
C. 25–35°C
D. Above 45°C

Correct Answer: C

Q46. Water stress reduces photosynthesis mainly by:

A. Destroying chlorophyll
B. Closing stomata
C. Lowering temperature
D. Increasing oxygen

Correct Answer: B

Q47. Blackman’s law states that rate of photosynthesis depends on:

A. All factors equally
B. Maximum factor
C. Limiting factor
D. Random factor

Correct Answer: C

Q48. Internal factors affecting photosynthesis include:

A. Light and temperature
B. CO₂ and water
C. Chlorophyll and leaf anatomy
D. Wind and humidity

Correct Answer: C

Q49. Increase in CO₂ concentration increases photosynthesis until:

A. Plant dies
B. Light becomes limiting
C. Oxygen increases
D. Chlorophyll decreases

Correct Answer: B

Q50. Photosynthesis is called backbone of life because it:

A. Produces ATP
B. Produces oxygen and food
C. Produces enzymes
D. Produces minerals

Correct Answer: B

Best Suited For

• CBSE Class 11 Annual Examinations
• NCERT-based MCQ practice
• Concept clarification and rapid revision

Targeting Exams

• CBSE Class 11 Biology Annual Examination

• CBSE School Unit Tests & Term Exams

• NCERT Chapter-wise MCQ Assessments

• Internal Assessments & Practice Worksheets

• Foundation preparation for Class 12 Biology

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