Here's how it works:
1. Electron transport chain: Electrons from the breakdown of glucose (glycolysis and the Krebs cycle) are passed along a chain of protein complexes embedded in the inner mitochondrial membrane. This movement of electrons releases energy, which is used to pump protons (H+) across the membrane, creating a proton gradient.
2. Chemiosmosis: The proton gradient drives the movement of protons back across the membrane through a protein called ATP synthase. This movement of protons powers the enzyme ATP synthase, which uses the energy to add a phosphate group to ADP, forming ATP.
Oxidative phosphorylation is highly efficient, producing around 34 ATP molecules per glucose molecule.
Other processes that produce ATP include:
* Glycolysis: This process breaks down glucose into pyruvate, producing 2 ATP molecules per glucose molecule.
* Krebs cycle: This cycle breaks down pyruvate, producing 2 ATP molecules per glucose molecule.
* Substrate-level phosphorylation: This process produces a small amount of ATP by directly transferring a phosphate group from a substrate to ADP.
While these other processes contribute to ATP production, they are far less efficient than oxidative phosphorylation.
