Final answer:
NADPH formation does not occur during cyclic photophosphorylation in cyanobacteria; this process only generates ATP by cycling electrons back to photosystem I.
Step-by-step explanation:
NADPH formation does not occur during cyclic photophosphorylation in cyanobacteria; this process only generates ATP by cycling electrons back to photosystem I. The process that does not occur during cyclic photophosphorylation in cyanobacteria is NADPH formation. During cyclic photophosphorylation, the excited electron is transferred within an electron transport chain and is eventually returned to the reaction center, allowing the production of ATP through a proton gradient.
This process only produces ATP, as the electrons are cycled back to photosystem I without the reduction of NADP+ to NADPH. The oxygen release, electron flow from water to photosystem II, and proton pumping, associated with non-cyclic photophosphorylation, where both ATP and NADPH are produced, do not occur within the cyclic process.