Here's how it works:
1. Electron transport chain: Electrons are passed down a chain of proteins within the inner mitochondrial membrane, releasing energy along the way.
2. Proton pumping: This energy is used to pump protons from the mitochondrial matrix (the space inside the mitochondria) to the intermembrane space (the space between the inner and outer mitochondrial membranes). This creates a proton gradient, with a higher concentration of protons in the intermembrane space.
3. ATP synthase: The proton gradient drives the movement of protons back across the membrane, through a protein complex called ATP synthase.
4. ATP production: The movement of protons through ATP synthase powers the enzyme to convert ADP (adenosine diphosphate) and inorganic phosphate into ATP (adenosine triphosphate), the energy currency of cells.
Therefore, the direct result of proton movement across the mitochondrial membrane is the production of ATP.
