Class 11 Biology MCQ Chapter 11 Photosynthesis in Higher Plants
Want to practice Class 11 Biology MCQ Chapter 11 Photosynthesis in Higher Plants English Medium? This article brings you important MCQ questions with answers that will help AHSEC Higher Secondary First Year students prepare better for examinations.
The chapter Photosynthesis in Higher Plants explains how green plants prepare their own food using sunlight, water, and carbon dioxide. Students will learn about photosynthetic pigments, chloroplasts, light reactions, dark reactions, Calvin cycle, C3 and C4 pathways, photorespiration, and factors affecting photosynthesis. These topics are very important for understanding plant physiology and are frequently asked in examinations.
The MCQs provided here are based on the latest AHSEC syllabus and exam pattern. They are designed to help students revise important concepts, improve their understanding, and test their knowledge in a simple and effective way. Regular practice can make revision easier and boost confidence before exams.
Whether you are preparing for school tests, annual exams, or the AHSEC HS First Year Examination, these MCQ solutions will help you strengthen your Biology preparation and score higher marks.
Unit IV. Plant Physiology
Photosynthesis in Higher Plants
VSA & MCQ
I. Short Answer Questions (1 Mark Each)
Q1. What is the dual role of RuBisCO enzyme?
Ans: It acts both as a carboxylase (fixes CO₂) and as an oxygenase (binds O₂ leading to photorespiration).
Q2. Why is RuBisCO more effective as a carboxylase in C₄ plants?
Ans: Due to high CO₂ concentration in bundle sheath cells, which suppresses oxygenase activity.
Q3. What is the primary photosynthetic pigment?
Ans: Chlorophyll a.
Q4. Can chlorophyll b alone carry out photosynthesis?
Ans: No, it cannot function independently without chlorophyll a.
Q5. What is the role of accessory pigments?
Ans: They absorb additional wavelengths of light and transfer energy to chlorophyll a.
Q6. Why do leaves turn yellow in darkness?
Ans: Chlorophyll breaks down, revealing carotenoid pigments.
Q7. Which pigment is more stable in leaves?
Ans: Carotenoids.
Q8. Why are shaded leaves darker green?
Ans: Due to higher chlorophyll content for better light absorption.
Q9. What is the first stable product of C₃ pathway?
Ans: 3-phosphoglycerate (3-PGA).
Q10. What is the first stable product of C₄ pathway?
Ans: Oxaloacetate (OAA).
Q11. What is photorespiration?
Ans: A process where RuBisCO fixes oxygen instead of CO₂, reducing photosynthetic efficiency.
Q12. Which enzyme fixes CO₂ in C₄ plants initially?
Ans: PEP carboxylase.
Q13. What is light saturation point?
Ans: The point beyond which increase in light does not increase photosynthesis.
Q14. What limits photosynthesis at low light intensity?
Ans: Light itself.
Q15. What factors may limit photosynthesis at high light intensity?
Ans: CO₂ concentration and temperature.
II. Multiple Choice Questions (MCQs)
Q1. RuBisCO functions as
(a) Only carboxylase
(b) Only oxygenase
(c) Both carboxylase and oxygenase
(d) None
Ans: (c)
Q2. In C₄ plants, RuBisCO mainly acts as
(a) Oxygenase
(b) Carboxylase
(c) Reductase
(d) Hydrolase
Ans: (b)
Q3. The primary pigment in photosynthesis is
(a) Chlorophyll b
(b) Carotene
(c) Chlorophyll a
(d) Xanthophyll
Ans: (c)
Q4. Accessory pigments help in
(a) CO₂ fixation
(b) Absorbing additional light
(c) ATP synthesis
(d) Water splitting
Ans: (b)
Q5. Leaves in dark become yellow due to
(a) Increase in chlorophyll
(b) Breakdown of carotenoids
(c) Breakdown of chlorophyll
(d) Increase in starch
Ans: (c)
Q6. More stable pigment is
(a) Chlorophyll a
(b) Chlorophyll b
(c) Carotenoids
(d) All equal
Ans: (c)
Q7. Dark green leaves are found in
(a) Sunny plants
(b) Shade plants
(c) Aquatic plants
(d) Desert plants
Ans: (b)
Q8. First stable product in C₃ cycle is
(a) OAA
(b) PGA
(c) RuBP
(d) Glucose
Ans: (b)
Q9. First stable product in C₄ cycle is
(a) PGA
(b) Glucose
(c) OAA
(d) RuBP
Ans: (c)
Q10. Initial CO₂ fixation enzyme in C₄ plants is
(a) RuBisCO
(b) PEP carboxylase
(c) ATP synthase
(d) NADP reductase
Ans: (b)
Q11. Photorespiration occurs due to
(a) High CO₂
(b) High O₂
(c) Low light
(d) High water
Ans: (b)
Q12. Light saturation point means
(a) Minimum light
(b) Maximum CO₂
(c) No increase in photosynthesis after a point
(d) Zero photosynthesis
Ans: (c)
Q13. Limiting factor at low light is
(a) CO₂
(b) Temperature
(c) Light
(d) Oxygen
Ans: (c)
Q14. In high light, limiting factor is often
(a) Water
(b) CO₂
(c) Oxygen
(d) Pigments
Ans: (b)
Q15. C₄ plants minimize
(a) Respiration
(b) Transpiration
(c) Photorespiration
(d) Digestion
Ans: (c)
Q16. Kranz anatomy is seen in
(a) C₃ plants
(b) C₄ plants
(c) Both
(d) None
Ans: (b)
Q17. Calvin cycle occurs in
(a) Mesophyll cells only
(b) Bundle sheath cells only (in C₄)
(c) Roots
(d) Stem
Ans: (b)
Q18. Cyclic photophosphorylation produces
(a) ATP only
(b) NADPH only
(c) Both
(d) Oxygen
Ans: (a)
Q19. Non-cyclic photophosphorylation produces
(a) ATP only
(b) NADPH only
(c) Both ATP and NADPH
(d) None
Ans: (c)
Q20. Oxygen evolution occurs in
(a) Cyclic
(b) Non-cyclic
(c) Both
(d) None
Ans: (b)
Q21. Electrons return to same chlorophyll in
(a) Non-cyclic
(b) Cyclic
(c) Both
(d) None
Ans: (b)
Q22. Bundle sheath cells are prominent in
(a) C₃
(b) C₄
(c) Both
(d) None
Ans: (b)
Q23. Photosynthesis efficiency is higher in
(a) C₃ plants
(b) C₄ plants
(c) Both equal
(d) None
Ans: (b)
Q24. Oxygenase activity of RuBisCO leads to
(a) Photosynthesis
(b) Respiration
(c) Photorespiration
(d) Digestion
Ans: (c)
Q25. Pigments present in thylakoid are
(a) Only chlorophyll a
(b) Only chlorophyll b
(c) Chlorophyll and accessory pigments
(d) None
Ans: (c)
Q26. Light reaction occurs in
(a) Stroma
(b) Thylakoid
(c) Cytoplasm
(d) Nucleus
Ans: (b)
Q27. Dark reaction occurs in
(a) Thylakoid
(b) Stroma
(c) Ribosome
(d) Golgi
Ans: (b)
Q28. PEP stands for
(a) Phosphoenol pyruvate
(b) Pyruvate
(c) Phosphate enzyme protein
(d) None
Ans: (a)
Q29. CO₂ concentration is highest in
(a) Mesophyll
(b) Bundle sheath (C₄)
(c) Roots
(d) Stem
Ans: (b)
Q30. Shade leaves contain more
(a) Water
(b) Chlorophyll
(c) Oxygen
(d) Sugar
Ans: (b)
