Non-cyclic photophosphorylation is a two-stage process that involves two different chlorophyll photosystems. It is a light reaction that occurs on thylakoid membranes inside the chloroplast.
Non-cyclic photophosphorylation begins when a water molecule is broken down by a process called photolysis. Next, a photon is absorbed and the light causes a chain reaction that transfers energy to the core. This in turn excites the two electrons transferred to pheophytin. Taking electrons from another molecule of water makes up this deficit. These electrons transfer from pheophytin to plastoquinone and once further broken down, are released. Two H+ ions are then released and the electrons then through Cyt b6 and Cyt f, and then through plastocyanin. This creates a gradient, which provides the energy for regeneration of ATP.