As a research scientist, you measure the amount of ATP and NADPH consumed by the Calvin cycle in 1 hour. You find that 30,000 molecules of ATP were consumed, but only 20,000 molecules of NADPH were consumed. Where did the extra ATP molecules come from?
A) photosystem II
B) photosystem I
C) cyclic electron flow
D) linear electron flow
E) chlorophyll

Question

Quizplus · Accepted Answer

Cyclic electron flow can produce additional ATP without the consumption of NADPH. This occurs when electrons cycle back from Ferredoxin to the Cytochrome complex instead of being passed to NADP+ to make NADPH. Therefore, the extra ATP consumed during the Calvin cycle may have come from cyclic electron flow.

As a Research Scientist, You Measure the Amount of ATP