In noncyclic photophosphorylation, oxidized chlorophyll in photosystem I returns to its reduced state by
A) splitting water.
B) accepting electrons from photosystem II through the electron transport chain.
C) absorbing two photons of light.
D) taking electrons from NADPH.
E) hydrolyzing ATP.

Question

Quizplus · Accepted Answer

In noncyclic photophosphorylation, photosystem I (PSI) does not receive replacement of its lost electrons from water. Instead, it receives electrons via the electron transport chain from photosystem II (PSII) after they have been excited by light and passed through electron carriers, including cytochrome b6f. This process permits the re-reduction of PSI's reaction center chlorophyll prior to its role in the production of NADPH.

In Noncyclic Photophosphorylation, Oxidized Chlorophyll in Photosystem I Returns to Its