Explain the process of Oxidative Phosphorylation in cellular respiration
Oxidative Phosphorylation is the final stage in cellular respiration. It is an oxygen requiring process which involves the creation of energy, in the form of ATP, through the process of chemiosmosis. The main components of this process include an electron transport chain, the coenzymes redNAD and redFAD and the enzyme ATP Synthase. After leaving the Krebs cycle, the coenzymes redNAD and redFAD are transported to an electron transport train located in the inner membrane of the mitochondria. At the start of the chain, they release hydrogen atoms to reform NAD and FAD. These hydrogen atoms then dissociate to form a proton and a high energy electron. The high energy electron then enters the electron transport chain. An electron transport chain is a series of 4 protein complexes, at which the high energy electron engages in exothermic redox reactions as it travels across the chain. The energy released from these reactions is used to actively transport protons across the inner mitochondrial membrane into the intermembrane space. Here, the concentration of protons increases quickly creating a steep concentration gradient. However, the inner mitochondrial membrane is impermeable to protons so they must travel through the membrane via a membrane protein, the enzyme ATP Synthase. This enzyme drives the formation of ATP. At the end of the electron transport chain is a complex named Cytochrome C Oxidase. Here, an oxygen atom combines with two hydrogen ions and electrons to form H2O, one of the products of cellular respiration.
