During photosynthesis, in the electron transport chain, ATP synthesis takes place when electrons move from:

Explanation

When an electron leaves PSII, it is transferred first to a small organic molecule (plastoquinone, Pq), then to a cytochrome complex (Cyt), and finally to a copper-containing protein called plastocyanin (Pc). As the electron moves through this electron transport chain, it goes from a higher to a lower energy level, releasing energy. Some of the energy is used to pump protons H+ from the stroma (outside of the thylakoid) into the thylakoid interior. This transfer of H+, along with the release of H+ from the splitting of water, forms a proton gradient that will be used to make ATP. It occurs when electrons move from Cyt b6-f complex to Pc.