A movement of electrons between photosystem II and photosystem I

B oxidation of water

C oxidation of NADPH

D absorption of photons by chloroplast pigments

E higher concentration of H⁺ inside versus outside the thylakoid membranes

The concentration gradient resulting from photosynthetic electron transport drives protons through a channel of the CF1 ATP Synthase enzyme. This movement of protons from a region of high concentration (inner thylakoid space) to low concentration (stroma) activates the conversion of ADP and P_i to ATP.