Practice question · Multiple choice
Why does the Calvin cycle stop within minutes of darkness, despite being called light-independent?
Hints
- The name refers to what the cycle uses directly, not to what supplies it.
- It runs on ATP and NADPH, and those come from the light reactions.
Show the answer
A. It depends on ATP and NADPH that only the light reactions supply
Why
The cycle uses no photons itself, which is what the name means, but it burns ATP and NADPH that only the light reactions make, and the cell holds only a small pool. Once that pool is spent the cycle halts.
Practise Photosynthesis and the Oxygen Revolution
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