The proton pumps embedded in the thylakoid membrane are directly responsible for ATP synthesis. Thylakoid membrane encloses thylakoid in chloroplasts of the plant cell. These are the regions that participate in the process of photosynthesis. The proton pumps create a proton motive force (PMF) across the membrane and this proton gradient drives the formation of ATP molecules from ADP molecules. The mechanism is somewhat similar to the ATP formation in mitochondria of eukaryotic cells. When light is incident on cells, water molecules are split to release electrons and protons, along with oxygen molecules. These protons are generated in thylakoid lumen and over time a proton gradient is built up. The chemical potential of such a gradient is used to convert ADP to ATP using ATP synthase.

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