As a research scientist, you measure the amount of ATP and NADPH consumed by the Calvin cycle in 1 hour. You find 30,000 molecules of ATP consumed, but only 20,000 molecules of NADPH. Where did the extra ATP molecules come from?

The question is incomplete as it does not have the options which are:

A) photosystem II

B) photosystem I

C) cyclic electron flow

D) linear electron flow

E) chlorophyll

Cyclic electron flow

Explanation:

The plants produce ATP molecule by the process of a light-dependent phase of photosynthesis which produces ATP and NADPH molecules.

The ATP and NADPH are produced by the non-cyclic flow of electrons called Z-scheme but when the plant needs extra ATP molecules, they produce more ATP by the cyclic electron flow.

The cyclic electron flow begins when the P₇₀₀ activates electron which then transferred to ferredoxin and then to cyt b₆f and then to plastocyanin. This is repeated and produce ATP molecules escaping the production of NADPH.

Thus, Cyclic electron flow is correct.