Question

The Calvin cycle could not occur without the light reactions. Which of the following statements describes why this is the case?

a) The Calvin cycle produces ATP for the light reactions.
b) The Calvin cycle produces oxygen for the light reactions.
c) The Calvin cycle uses ATP and NADPH from the light reactions.
d) The Calvin cycle inhibits the light reactions.

Answer 1

The Calvin cycle requires ATP and NADPH produced during the light-dependent reactions of photosynthesis to occur, therefore it cannot function without them.

Step-by-step explanation:

The Calvin cycle could not occur without the light reactions because the Calvin cycle uses ATP and NADPH from the light reactions. During the light-dependent reactions, which take place in the thylakoid membrane, light energy is used to produce ATP and NADPH. The Calvin cycle, occurring in the stroma, then utilizes the chemical energy carried by these molecules to convert carbon dioxide from the atmosphere into carbohydrates, specifically a three-carbon molecule called glyceraldehyde-3-phosphate (G3P). Therefore, the correct statement describing why the Calvin cycle could not occur without the light reactions is 'The Calvin cycle uses ATP and NADPH from the light reactions', which aligns with option c).