Oxidative phosphorylation is made up of two closely connected components: the electron transport chain and chemiosmosis. The electron transport chain in the cell is the site of oxidative phosphorylation. The NADH and succinate generated in the citric acid cycle are oxidized, releasing the energy of O2 to power the ATP synthase.
Oxidative phosphorylation (UK /ɒkˈsɪd.ə.tɪv/, US /ˈɑːk.sɪˌdeɪ.tɪv/[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). In eukaryotes, this takes place inside mitochondria. Almost all aerobic organisms carry out oxidative phosphorylation. This pathway is so pervasive because it releases more energy than alternative fermentation processes such as anaerobic glycolysis.
The energy stored in the chemical bonds of glucose is released by the cell in the citric acid cycle, producing carbon dioxide and the energetic electron donors NADH and FADH. Oxidative phosphorylation uses these molecules and O2 to produce ATP, which is used throughout the cell whenever energy is needed. During oxidative phosphorylation, electrons are transferred from the electron donors to a series of electron acceptors in a series of redox reactions ending in oxygen, whose reaction releases half of the total energy.[2]
In eukaryotes, these redox reactions are catalyzed by a series of protein complexes within the inner membrane of the cell's mitochondria, whereas, in prokaryotes, these proteins are located in the cell's outer membrane. These linked sets of proteins are called the electron transport chain. In eukaryotes, five main protein complexes are involved, whereas in prokaryotes many different enzymes are present, using a variety of electron donors and acceptors.
The energy transferred by electrons flowing through this electron transport chain is used to transport protons across the inner mitochondrial membrane, in a process called electron transport. This generates potential energy in the form of a pH gradient and the resulting electrical potential across this membrane. This store of energy is tapped when protons flow back across the membrane and down the potential energy gradient, through a large enzyme called ATP synthase in a process called chemiosmosis. The ATP synthase uses the energy to transform adenosine diphosphate (ADP) into adenosine triphosphate, in a phosphorylation reaction. 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.
Although oxidative phosphorylation is a vital part of metabolism, 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 and senescence. The enzymes carrying out this metabolic pathway are also the target of many drugs and poisons that inhibit their activities.
^"oxidative Meaning in the Cambridge English Dictionary". dictionary.cambridge.org. Archived from the original on 24 January 2018. Retrieved 28 April 2018.
^Voet, D.; Voet, J. G. (2004). "Biochemistry", 3rd ed., p. 804, Wiley.ISBN 0-471-19350-X.
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Oxidativephosphorylation (UK /ɒkˈsɪd.ə.tɪv/, US /ˈɑːk.sɪˌdeɪ.tɪv/ ) or electron transport-linked phosphorylation or terminal oxidation is the metabolic...
of the ATP produced by aerobic cellular respiration is made by oxidativephosphorylation. The energy released is used to create a chemiosmotic potential...
gradient to make ATP. This process is called oxidativephosphorylation because it uses energy released by the oxidation of NADH and FADH2 to phosphorylate ADP...
fed into the oxidativephosphorylation (electron transport) pathway. The net result of these two closely linked pathways is the oxidation of nutrients...
with oxidativephosphorylation with ATP synthase. In eukaryotic organisms, the electron transport chain, and site of oxidativephosphorylation, is found...
components of the cell, including proteins, lipids, and DNA. Oxidative stress from oxidative metabolism causes base damage, as well as strand breaks in...
related problem for aerobic organisms is oxidative stress. Here, processes including oxidativephosphorylation and the formation of disulfide bonds during...
eukaryotes are (1) glycolysis, (2) the citric acid cycle/oxidativephosphorylation, and (3) beta-oxidation. The overall process of oxidizing glucose to carbon...
: 464 An electrochemical gradient is essential to mitochondrial oxidativephosphorylation. The final step of cellular respiration is the electron transport...
An uncoupler or uncoupling agent is a molecule that disrupts oxidativephosphorylation in prokaryotes and mitochondria or photophosphorylation in chloroplasts...
achieved throughout processes such as substrate-level phosphorylation, oxidativephosphorylation, and photophosphorylation, all of which facilitate the...
in the pathway. The first is the oxidative phase, in which NADPH is generated, and the second is the non-oxidative synthesis of 5-carbon sugars. For...
(ADP) in a process referred to as oxidativephosphorylation. ATP is also synthesized by substrate-level phosphorylation during glycolysis. ATP is synthesized...
This structure traps one proton, which is quite helpful for oxidativephosphorylation. As the head group forms such compact bicycle structure, the head...
compartment of the cell. For instance, the electron transport chain and oxidativephosphorylation all take place in the mitochondrial membrane.: 73, 74 & 109 In...
and oxidativephosphorylation. The citric acid cycle produces NADH and FADH2 through oxidation that will be reduced in oxidativephosphorylation to produce...
respiratory chain in the inner mitochondrial membrane carries out oxidativephosphorylation. Three enzyme complexes are responsible for the electron transport:...
few compared to the second and third pathways, Krebs cycle and oxidativephosphorylation. Even if there is no oxygen present, glycolysis can continue to...
significant oxidative stress in the mitochondria with high mutation rates of mitochondrial DNA. Hypothesized links between aging and oxidative stress are...
which ATP is produced in this manner is about 100 times that of oxidativephosphorylation. The pH in the cytoplasm quickly drops when hydrogen ions accumulate...
factors) have been implicated in Leigh disease. Disorders of oxidativephosphorylation, the process by which cells produce their main energy source of...
including animals and bacteria. CoQ10 plays a role in mitochondrial oxidativephosphorylation, aiding in the production of adenosine triphosphate (ATP), which...
enzymes used for mitochondrial and peroxisomal β-oxidation: The NADH formed in the third oxidative step cannot be reoxidized in the peroxisome, so reducing...
borne fuels unable to be delivered to muscle cells adequately for oxidativephosphorylation). Three systems can be selectively recruited, depending on the...
acid cycle), and oxidativephosphorylation. C6H12O6 + 6 O2 + 38 ADP + 38 phosphate → 6 CO2 + 44 H2O + 38 ATP In Oxidativephosphorylation, ATP is synthesized...
beta oxidative cut of the acyl-CoA molecule eventually yields 5 ATP molecules in oxidativephosphorylation. The acetyl-CoA produced by beta oxidation enters...
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