atp synthase gets the energy to make atp from electron transport chain.
where does atp synthase get the energy to make atp?
electron transport chain
according to the chemiosmotic coupling hypothesis, proposed by nobel prize in chemistry winner peter d. mitchell, the electron transport chain and oxidative phosphorylation are coupled by a proton gradient across the inner mitochondrial membrane. the efflux of protons from the mitochondrial matrix creates an electrochemical gradient (proton gradient). this gradient is used by the ff atp synthase complex to make atp via oxidative phosphorylation. atp synthase is sometimes described as "complex v" of the electron transport chain. the f component of atp synthase acts as an ion channel that provides for a proton flux back into the mitochondrial matrix. it is composed of a, b and c subunits. protons in the inter-membranous space of mitochondria first enters the atp synthase complex through "a" subunit channel. then protons move to the c subunits. the number of c subunits it has determines how many protons it will require to make the f turn one full revolution. for example, in humans, there are 8 c subunits, thus 8 protons are required. after "c" subunits, protons finally enters matrix using "a" subunit channel that opens into the mitochondrial matrix. this reflux releases free energy produced during the generation of the oxidized forms of the electron carriers (nad and q). the free energy is used to drive atp synthesis, catalyzed by the f component of the complex.
electron transport chain
the evolution of atp synthase is thought to have been modular whereby two functionally independent subunits became associated and gained new functionality. this association appears to have occurred early in evolutionary history, because essentially the same structure and activity of atp synthase enzymes are present in all kingdoms of life. the f-atp synthase displays high functional and mechanistic similarity to the v-atpase. however, whereas the f-atp synthase generates atp by utilising a proton gradient, the v-atpase generates a proton gradient at the expense of atp, generating ph values of as low as 1.
atp synthase