Noncyclic Photophosphorylation Produces

Question

Noncyclic photophosphorylation produces
A) ATP only.
B) oxygen.
C) NADPH only.
D) ATP and NADPH.
E) water and ATP.

Accepted Answer

Noncyclic photophosphorylation produces both ATP and NADPH. During noncyclic photophosphorylation, light energy is used to energize electrons in photosystem II, which are then passed through a series of carriers, ultimately providing energy to pump protons across the thylakoid membrane. The resulting proton gradient drives ATP synthesis through chemiosmosis. At the same time, photosystem I receives electrons from photosystem II, replenishing its own electron supply. These electrons are then further energized by light energy and used to reduce NADP+ to NADPH. So, noncyclic photophosphorylation produces both ATP and NADPH, which are used during the light-independent reactions of photosynthesis to make glucose.