Biology

If the thylakoid membrane became permeable to protons, the proton gradient would dissipate, and ATP synthesis would stop.

In the light-dependent reactions of photosynthesis, one of the crucial processes is the generation of a proton gradient across the thylakoid membrane. When water is split in the light-dependent reactions, protons (H⁺) are released into the thylakoid lumen, creating a high concentration of protons inside the thylakoid membrane compared to the stroma (outside the thylakoid membrane). This difference in proton concentration creates a proton gradient. The energy from this gradient is used by ATP synthase to produce ATP, which is then used in the Calvin cycle (light-independent reactions) for glucose synthesis.

If the thylakoid membrane became permeable to protons, the protons would flow back into the stroma without passing through ATP synthase, effectively dissipating the proton gradient. Without this gradient, ATP synthesis would stop because the driving force for ATP production would no longer exist.