what causes cyclic photophosphorylation to occur in photosynthesis
Cyclic photophosphorylation requires photosystem I, but not photosystem II. Light-dependent electron transport occurs in the thylakoid membranes, where electrons follow a cyclic pathway, returning to the photosystem I reaction center.yclic photophosphorylation requires photosystem I, but not photosystem II. Light-dependent electron transport occurs in the thylakoid membranes, where electrons follow a cyclic pathway, returning to the photosystem I reaction center.