How is ATP produced by cyclic electron flow?
In cyclic electron flow, electrons begin at the acceptor molecule and are passed to an electron transport chain. This ETC, like the one connecting the two Photosystems, is a series of receptor molecules able to pass along electrons but the flow is from photosystem I directly back to Photosystem I. These electrons begin at the acceptor molecule for Photosystem I and wind up back at Photosystem I again. As the electrons slide along this chain of receptor molecules in cyclic electron flow, they lose energy. This energy is in turn stored in ATP molecules. Energy from the electrons involved in cyclic electron flow is used to produce ATP.
