Question

What would be the consequences to NADPH production if the redox potential of pC (plastocyanin) were altered to be more negative than the redox potential of cytochrome b6-f?Choose one:

A. NADPH production would not be altered since NADPH is produced from photosystem I.
B. NADPH production would halt since pC would no longer accept electrons from the cytochrome b6-f complex, blocking the electron transport chain.
C. NADPH would be broken down since the electron transport chain would work backward.
D. NADPH production would be higher since pC would be a better electron donor.

Answer 1

If the redox potential of pC (plastocyanin) were altered to be more negative than the redox potential of cytochrome b6-f, NADPH production would halt since pC would no longer accept electrons from the cytochrome b6-f complex, blocking the electron transport chain.

Step-by-step explanation:

If the redox potential of pC (plastocyanin) were altered to be more negative than the redox potential of cytochrome b6-f, NADPH production would halt since pC would no longer accept electrons from the cytochrome b6-f complex, blocking the electron transport chain. This means that the flow of electrons from photosystem II to photosystem I would be disrupted, preventing the reduction of NADP+ to NADPH. As a result, the production of NADPH, which is important for the synthesis of glucose in the Calvin cycle, would be significantly reduced or completely stopped.