Photosynthesis Quiz - CBSE Class 12 Biology

Free practice quiz: Photosynthesis (CBSE Class 12 Biology). 20 multiple-choice questions with answers and explanations. Play online, no sign-up needed.

This CBSE Class 12 Biology practice quiz has 20 multiple-choice questions on Photosynthesis, and 20 of them come with an explanation. Try the 5 sample questions below (tap an option to check yourself), then play the full quiz online. No sign-up needed.

Sample questions

1. What is the primary product of the light-dependent reactions of photosynthesis?

   1. Glucose
   2. ATP and NADPH
   3. Oxygen
   4. Carbon dioxide
   Show answer

   Answer: B. ATP and NADPH

   The light-dependent reactions use light energy to generate ATP and NADPH, which are then used in the light-independent reactions to produce glucose.

2. Explain photorespiration and its impact on photosynthetic efficiency.

   1. A process that enhances CO2 fixation
   2. A process that increases ATP production
   3. A wasteful process that competes with carbon fixation
   4. A process that improves water use efficiency
   Show answer

   Answer: C. A wasteful process that competes with carbon fixation

   Photorespiration is a process where RuBisCo binds with oxygen instead of carbon dioxide, leading to a net loss of energy and reduced photosynthetic efficiency.

3. Explain the chemiosmotic hypothesis in relation to ATP synthesis during photosynthesis.

   1. ATP is synthesized directly by light
   2. ATP is synthesized through substrate-level phosphorylation
   3. ATP synthesis is driven by a proton gradient across the thylakoid membrane
   4. ATP synthesis is independent of electron transport
   Show answer

   Answer: C. ATP synthesis is driven by a proton gradient across the thylakoid membrane

   The chemiosmotic hypothesis explains how the proton gradient generated during electron transport drives ATP synthesis via ATP synthase in the thylakoid membrane.

4. Explain the role of photolysis in the light-dependent reactions.

   1. It reduces NADP+
   2. It generates ATP
   3. It splits water molecules to release electrons, protons, and oxygen
   4. It fixes carbon dioxide
   Show answer

   Answer: C. It splits water molecules to release electrons, protons, and oxygen

   Photolysis, or the splitting of water molecules, provides electrons to replenish those lost by photosystem II, releasing oxygen as a byproduct.

5. Explain the concept of quantum efficiency in photosynthesis and its importance in understanding photosynthetic limitations.

   1. It is irrelevant
   2. It is the efficiency of light absorption and conversion to chemical energy
   3. It measures the rate of respiration
   4. It is constant irrespective of conditions
   Show answer

   Answer: B. It is the efficiency of light absorption and conversion to chemical energy

   Quantum efficiency measures how efficiently absorbed photons are converted into chemical energy, providing insights into photosynthetic limitations under various conditions.

More questions in this quiz

Answers and explanations are in the full quiz.

1. What is the role of chlorophyll in photosynthesis?
2. Where does the Calvin cycle take place?
3. What is RuBisCo's role in the Calvin cycle?
4. What are C4 plants, and how do they differ from C3 plants?
5. Describe the process of cyclic photophosphorylation and its significance.
6. What are the different types of photosynthetic pigments and their roles?
7. How does the structure of the chloroplast facilitate photosynthesis?
8. Discuss the factors affecting the rate of photosynthesis (light intensity, CO2 concentration, temperature).
9. Compare and contrast the photosynthetic mechanisms of C3, C4, and CAM plants.
10. Describe the Z-scheme of electron transport in photosynthesis and its significance.
11. Analyze the impact of environmental stresses (e.g., drought, salinity, high light intensity) on photosynthesis.
12. Discuss the application of photosynthetic principles in enhancing crop productivity.
13. Critically evaluate the different models proposed for explaining the mechanism of oxygen evolution during photosynthesis.
14. Discuss the role of light harvesting complexes in optimizing the efficiency of light absorption and energy transfer in photosynthesis.
15. Investigate the potential of artificial photosynthesis in addressing global energy challenges. Discuss its current limitations and future prospects.

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