Question

Assertion :Photorespiration decreases net photosynthesis. Reason: Rate of respiration in dark and light is almost same in all plants.

• A. Both Assertion and Reason are correct and Reason is the correct explanation for Assertion.
• B. Both Assertion and Reason are correct but Reason is not the correct explanation for Assertion.
• C. Assertion is correct but Reason is incorrect.
• D. Assertion is incorrect but Reason is correct.

Answer 1

The correct option is C Assertion is correct but Reason is incorrect.

• Photorespiration is a biochemical process which results from the light-dependent uptake of oxygen and release of carbon dioxide, contrary to the general pattern of photosynthesis. Photorespiration takes place in green plants at the same time that photosynthesis does. In photosynthesis carbon dioxide is taken in, and in photorespiration, carbon dioxide is given off.
• Thus, these two processes work against each other. In short, photorespiration decreases the net amount of carbon dioxide which is converted into sugars by a photosynthesizing plant.
• By interfering with photosynthesis in this way, photorespiration may significantly limit the growth rate of some plants. Respiration is not affected by either light or dark. The rate of respiration does not depend on photorespiration or photosynthesis.

Hence, Assertion is correct but Reason is incorrect. So, the answer is C.