ABSTRACT
In eukaryotes, electron transport and oxidative phosphorylation occur in the inner membrane of mitochondria. These processes re-oxidize the NADH and FADH2 that arise from the citric acid cycle, glycolysis and fatty acid oxidation and trap the energy released as adenosine triphosphate (ATP). In prokaryotes, the components of electron transport and oxidative phosphorylation are located in the plasma membrane. The oxidation–reduction potential, E, (or redox potential) is a measure of the affinity of a substance for electrons and is measured relative to hydrogen. A positive redox potential means that the substance has a higher affinity for electrons than does hydrogen and so would accept electrons from hydrogen. All of the electron carriers in the electron transport chain interact according to their redox potentials. Succinate dehydrogenase catalyzes the oxidation of succinate to fumarate in the citric acid cycle.
