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Oxidative phosphorylation (UK / ɒ k ˈ s ɪ d. ə. t ɪ v /, US / ˈ ɑː k. s ɪ ˌ d eɪ. t ɪ v / [1]) or electron transport-linked phosphorylation or terminal oxidation is the metabolic pathway in which cells use enzymes to oxidize nutrients, thereby releasing chemical energy in order to produce adenosine triphosphate (ATP).
Phosphorylation of glucose and fructose 6-phosphate uses two ATP from the cytoplasm. Glycolysis pay-off phase 4 Substrate-level phosphorylation 2 NADH 3 or 5 Oxidative phosphorylation: Each NADH produces net 1.5 ATP (instead of usual 2.5) due to NADH transport over the mitochondrial membrane Oxidative decarboxylation of pyruvate 2 NADH 5
The overall process of creating energy in this fashion is termed oxidative phosphorylation. The same process takes place in the mitochondria, where ATP synthase is located in the inner mitochondrial membrane and the F 1-part projects into the mitochondrial matrix. By pumping proton cations into the matrix, the ATP-synthase converts ADP into ATP.
ADP and phosphate are needed as precursors to synthesize ATP in the payoff reactions of the TCA cycle and oxidative phosphorylation mechanism. [4] During the payoff phase of glycolysis, the enzymes phosphoglycerate kinase and pyruvate kinase facilitate the addition of a phosphate group to ADP by way of substrate-level phosphorylation. [5]
Oxidative phosphorylation – The last stage of the aerobic system produces the largest yield of ATP – a total of 34 ATP molecules. It is called oxidative phosphorylation because oxygen is the final acceptor of electrons and hydrogen ions (hence oxidative) and an extra phosphate is added to ADP to form ATP (hence phosphorylation).
The phosphate/oxygen ratio, or P/O ratio, refers to the amount of ATP produced from the movement of two electrons through a defined electron transport chain, terminated by reduction of an oxygen atom.
Oxidative phosphorylation contributes the majority of the ATP produced, compared to glycolysis and the Krebs cycle. While the ATP count is glycolysis and the Krebs cycle is two ATP molecules, the electron transport chain contributes, at most, twenty-eight ATP molecules. A contributing factor is due to the energy potentials of NADH and FADH 2.
Serine in an amino acid chain, before and after phosphorylation. In biochemistry, phosphorylation is the attachment of a phosphate group to a molecule or an ion. [1] This process and its inverse, dephosphorylation, are common in biology. [2] Protein phosphorylation often activates (or deactivates) many enzymes. [3] [4]