The Electron Transport Chain and Oxidative Phosphorylation Sample Clauses

The Electron Transport Chain and Oxidative Phosphorylation. The reduced coenzymes NADH and FADH2 donate electrons to the electron transport chain (ETC) (figure 1.5), which serves to convert the energy of these electrons into the high energy phosphate bonds of ATP, in a gradual and controlled manner. The protein complexes of the ETC contain a series of redox centres with gradually increasing reduction potentials. This allows the passage of electrons up the reduction gradient, whilst simultaneously pumping protons (H+) from the mitochondrial matrix into the inner mitochondrial membrane space. The proton gradient between the two compartments is then used by ATP synthase to synthesise ATP from ADP and inorganic phosphate (Pi). The process of electron transport is entirely dependent on molecular oxygen, which acts as the terminal electron acceptor. If the supply of oxygen is compromised then the protein complexes of the ETC remain in the reduced form. This inhibits generation of the mitochondrial membrane potential by proton efflux, and therefore also inhibits the activity of ATP synthase [36-37].