Oxidative phosphorylation is the metabolic pathway in which cells use enzymes to oxidize nutrients. It releases the chemical energy stored within in order to produce adenosine triphosphate. In most eukaryotes, this takes place inside mitochondria. The reaction is driven by the proton flow, which forces the rotation of a part of the enzyme.
About Oxidative phosphorylation in brief
Oxidative phosphorylation is the metabolic pathway in which cells use enzymes to oxidize nutrients. It releases the chemical energy stored within in order to produce adenosine triphosphate. In most eukaryotes, this takes place inside mitochondria. The energy of the double bond of oxygen is so much higher than that of carbon dioxide or organic molecules observed in alternative fermentation processes such as anaerobic glycolysis. The enzymes carrying out this metabolic pathway are also the target of many drugs and poisons that inhibit their activities. It is the terminal process of cellular respiration and accounts for high ATP yield. The amount of energy released by oxidative phosphorylated molecules is high compared to the amount produced by anaerilic fermentation. In the case of ATPs, somewhere between 30 and 36% of ATP is produced by O2, due to the high energy of O2 molecules, but only 2% produced by Glycolytic O2 and 30% by ATPs. The reaction is driven by the proton flow, which forces the rotation of a part of the enzyme; the ATP synthase is a rotary mechanical motor. It produces reactive oxygen species such as superoxide and hydrogen peroxide, which lead to propagation of free radicals, damaging cells and contributing to disease and, possibly, aging. In mitochondria, the largest part of energy is provided by the electrical potential of the alkaliphile bacteria. However, chloroplasts operate mainly on a small potential for the synthesis of ATP, and require a small pH difference on the membrane for the kinetics of ATP synthesis.
The electrochemical gradient drives the rotation and couples this motion to the production of ATP. The two components of the Proton-motive force are equivalent: the two components are thermodynamically equivalent: in mitochondria the large part of electrical energy is given by the N-side of the membrane, and in alkalipile bacteria the small part of electric energy is taken up by the P-side. The movement of protons across the inner mitochondrial membrane creates a pH gradient and an electrical potential across this membrane. This generates potential energy in the form of a proton-Motive force, which is often called the propton-m automotive force. This energy is tapped when protons flow back across the membrane and down the potential energy gradient, in a process called chemiosmosis. The ATP synth enzyme uses the energy to transform adenosin diphosphate into adenosina triph phosphate, in the phosphorylating reaction. It uses theenergy to complete the circuit and allow protons to flow down the electrochemical. gradient, back to the negative N- side of the membranes. The chain of redox reactions driving the flow of electrons through the electron transport chain, from electron donors such as NADH to electron acceptors such as oxygen and hydrogen, is an exergonic process – it releases energy, whereas the synthesis requires an input of energy.
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This page is based on the article Oxidative phosphorylation published in Wikipedia (as of Dec. 03, 2020) and was automatically summarized using artificial intelligence.
