Unit 2 Biochemistry: Careful measurements indicate that the Calvin cycle in a plant leaf is occurring very slowly. In such a situation, there is a reduced demand for both NADPH and ATP.

(a) What benefit (if any) would the light-dependent reactions still have for this plant?

(b) Can you think of any environmental conditions under which such a situation might arise?

Question

Careful measurements indicate that the Calvin cycle in a plant leaf is occurring very slowly. In such a situation, there is a reduced demand for both NADPH and ATP.

(a) What benefit (if any) would the light-dependent reactions still have for this plant?

(b) Can you think of any environmental conditions under which such a situation might arise?

fahr dat · Accepted Answer

(a) The light-dependent reactions would still be supplying the NADPH and ATP that the
Calvin cycle requires, even though it is occurring very slowly.

(b) This situation might arise if the plant is in a very hot or very dry environment. The stomata of
the leaf may close to conserve water, which would also block the intake of carbon dioxide.

Unit 2 Biochemistry

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