Photophosphorylation is the process in which ATP is produced, which is called as energy currency of the cell. During this process, ADP is phosphorylated to give ATP in presence of light energy. Related Theory During photophosphorylation, electrons move from water through PSII, intermediate chain of carriers, through PSI, and finally to NADP+ causing its reduction into NADPH2. Flow of electrons through the carriers linking PSII and PSI pump protons into the thylakoid lumen.