This leads to the formation of a proton gradient as the concentration builds on one side of the membrane. CO 2 is fixed into an organic molecule. ATP is produced. A proton gradient is formed. PSI and PS II play a role.
Water donates electrons to the photosynthetic electron transport chain.
Plants appear green because the photosystems prefer to absorb green light over all other visible wavelengths. The carotenoid donates an electron to chlorophyll a . The carotenoid donates an electron to the photosynthetic electron transport chain and then to chlorophyll a . The energy is released as light. Noncyclic electron flow produces ATP only.