QuestenaPractice that shows what to review next
SearchCreate a test
Question 32

Above its optimum temperature the rate of photosynthesis in a plant falls sharply. What causes that fall?

  1. The chlorophyll melts and can no longer absorb light
  2. The plant runs out of carbon dioxide at high temperatures
  3. The enzymes that control the reaction are denaturedCorrect answer
  4. The water in the leaf boils away and stops the reaction

Explanation

The reaction is controlled by enzymes, and heating them beyond a certain point changes the shape of their active sites so that they can no longer do their work, which is why the rate collapses instead of simply levelling off. The green pigment does not melt at temperatures a plant meets, and nothing about warming the air removes the gas supply.

Continue with this test

Start practice
Understand this topic (≈5 min)Back to test
Question 32: Above its optimum temperature the rate of photosynthesis in… · Plants and Photosynthesis · Questena