Which Statement Describes the Functioning of Photosystem II

Question

Which statement describes the functioning of photosystem II?
A) Light energy excites electrons in the thylakoid membrane electron transport chain.
B) Photons are passed along to a reaction-center chlorophyll.
C) The P680 chlorophyll donates a pair of protons to NADP⁺, which is thus converted to NADPH.
D) The electron vacancies in P680⁺ are filled by electrons derived from water.
E) The splitting of water yields molecular carbon dioxide as a by-product.

Accepted Answer

Photosystem II functions by using light energy to excite electrons in the thylakoid membrane electron transport chain. These electrons are then passed along to a reaction-center chlorophyll. The P680 chlorophyll donates a pair of electrons to a nearby electron acceptor, which sets off a series of redox reactions that eventually lead to the creation of ATP and NADPH. The electron vacancies in P680⁺ are then filled by electrons derived from water, which is split in a process called photolysis. This results in the release of oxygen as a by-product. The splitting of water does not yield molecular carbon dioxide as a by-product, so option E is incorrect.