Oxidative phosphorylation is a combination of two simultaneous processes; the electron transport chain and chemiosmotic coupling. The electron transport chain (also known as the respiratory chain) comprises 4 complexes located in the inner mitochondrial membrane. NADH and FADH2, produced from glycolysis and the Krebs cycle, release electrons at certain points in the chain, which are passed from one electron acceptor to the next. Each time an electron is passed from one complex to the next, it loses energy.
Chemiosmotic coupling harnesses the energy from the electron transport chain and uses it to transport H+ across the inner mitochondrial membrane, establishing a concentration gradient. ATP synthase is found in the inner mitochondrial membrane and this enzyme uses the energy from H+ ion flux to synthesize ATP. Three ATP molecules can be made from each pair of electrons from NADH and two ATP molecules are made from a pair of electrons from FADH2.View all products for Oxidative Phosphorylation »