Editing Metabolism (section)

===Oxidative phosphorylation===
{{further|Oxidative phosphorylation|Chemiosmosis|Mitochondrion}}

In oxidative phosphorylation, the electrons removed from organic molecules in areas such as the citric acid cycle are transferred to oxygen and the energy released is used to make ATP. This is done in [[eukaryote]]s by a series of proteins in the membranes of mitochondria called the [[electron transport chain]]. In [[prokaryote]]s, these proteins are found in the cell's [[bacterial cell structure|inner membrane]].<ref>{{cite journal | vauthors = Hosler JP, Ferguson-Miller S, Mills DA | title = Energy transduction: proton transfer through the respiratory complexes | journal = [[Annual Review of Biochemistry]] | volume = 75 | pages = 165–87 | year = 2006 | pmid = 16756489 | pmc = 2659341 | doi = 10.1146/annurev.biochem.75.062003.101730 }}</ref> These proteins use the energy from [[reducing agent|reduced]] molecules like NADH to pump [[proton]]s across a membrane.<ref>{{cite journal | vauthors = Schultz BE, Chan SI | title = Structures and proton-pumping strategies of mitochondrial respiratory enzymes | journal = [[Annual Review of Biophysics and Biomolecular Structure]] | volume = 30 | pages = 23–65 | year = 2001 | pmid = 11340051 | doi = 10.1146/annurev.biophys.30.1.23 | url = https://authors.library.caltech.edu/1623/1/SCHarbbs01.pdf | access-date = 11 November 2019 | archive-date = 22 January 2020 | archive-url = https://web.archive.org/web/20200122235247/https://authors.library.caltech.edu/1623/1/SCHarbbs01.pdf | url-status = live }}</ref>
[[File:ATPsyn.gif|thumb|right|Mechanism of [[ATP synthase]]. ATP is shown in red, ADP and phosphate in pink and the rotating stalk subunit in black.]]
Pumping protons out of the mitochondria creates a proton [[diffusion|concentration difference]] across the membrane and generates an [[electrochemical gradient]].<ref>{{cite journal | vauthors = Capaldi RA, Aggeler R | title = Mechanism of the F(1)F(0)-type ATP synthase, a biological rotary motor | journal = Trends in Biochemical Sciences | volume = 27 | issue = 3 | pages = 154–60 | date = March 2002 | pmid = 11893513 | doi = 10.1016/S0968-0004(01)02051-5 }}</ref> This force drives protons back into the mitochondrion through the base of an enzyme called [[ATP synthase]]. The flow of protons makes the stalk subunit rotate, causing the [[active site]] of the synthase domain to change shape and phosphorylate [[adenosine diphosphate]]—turning it into ATP.<ref name="Dimroth-2006"/>