<P> The two components of the proton - motive force are thermodynamically equivalent: In mitochondria, the largest part of energy is provided by the potential; in alkaliphile bacteria the electrical energy even has to compensate for a counteracting inverse pH difference . Inversely, chloroplasts operate mainly on ΔpH . However, they also require a small membrane potential for the kinetics of ATP synthesis . In the case of the fusobacterium Propionigenium modestum it drives the counter-rotation of subunits a and c of the F motor of ATP synthase . </P> <P> The amount of energy released by oxidative phosphorylation is high, compared with the amount produced by anaerobic fermentation . Glycolysis produces only 2 ATP molecules, but somewhere between 30 and 36 ATPs are produced by the oxidative phosphorylation of the 10 NADH and 2 succinate molecules made by converting one molecule of glucose to carbon dioxide and water, while each cycle of beta oxidation of a fatty acid yields about 14 ATPs . These ATP yields are theoretical maximum values; in practice, some protons leak across the membrane, lowering the yield of ATP . </P> <P> The electron transport chain carries both protons and electrons, passing electrons from donors to acceptors, and transporting protons across a membrane . These processes use both soluble and protein - bound transfer molecules . In mitochondria, electrons are transferred within the intermembrane space by the water - soluble electron transfer protein cytochrome c . This carries only electrons, and these are transferred by the reduction and oxidation of an iron atom that the protein holds within a heme group in its structure . Cytochrome c is also found in some bacteria, where it is located within the periplasmic space . </P> <P> Within the inner mitochondrial membrane, the lipid - soluble electron carrier coenzyme Q10 (Q) carries both electrons and protons by a redox cycle . This small benzoquinone molecule is very hydrophobic, so it diffuses freely within the membrane . When Q accepts two electrons and two protons, it becomes reduced to the ubiquinol form (QH); when QH releases two electrons and two protons, it becomes oxidized back to the ubiquinone (Q) form . As a result, if two enzymes are arranged so that Q is reduced on one side of the membrane and QH oxidized on the other, ubiquinone will couple these reactions and shuttle protons across the membrane . Some bacterial electron transport chains use different quinones, such as menaquinone, in addition to ubiquinone . </P>

Where does oxidation and reduction occur in oxidative phosphorylation
find me the text answering this question