The electron transfer chain is a series of enzyme and protein reactions within the inner mitochondrial membrane. Combined with oxidative phosphorylation, it converts energy in the form of the electron transfer potential of NADH and FADH2 into the energy within the terminal phosphate bond of ATP. Simultaneously, oxygen is consumed and water is produced.
NADH and FADH2 are derived from reactions in glycolysis, the beta-oxidation of fatty acids, the tricarboxylic acid cycle and other metabolic pathways. NADH enters the chain at the level of NADH dehydrogenase ultimately to produce 3 molecules of ATP. FADH2 enters the chain at the level of coenzyme Q to yield 2 molecules of ATP.
Oxidative phosphorylation is the mechanism by which the proton-pumping actions of the respiratory chain are transduced into ATP.
Last reviewed 01/2018