Figure 8.

Schematic mechanism of photosynthesis in the thylakoid membrane (ATP production). When light reaches the reaction center of PSI and PSII, the excited electrons from the reaction center are transferred. At this time, a proton gradient is formed across the membrane due to the electron transfer and water splitting, and the proton concentration of the thylakoid lumen increases. Thus, the proton is transferred through ATP synthase from the thylakoid lumen to the stroma. As a result, ATP is synthesized at the stroma in the cell.