Electron Transport Chain vs Oxidative Phosphorylation

oxidative phosphorylation

electron transport chain

energy input / usage utilizes products of the Krebs cycle driven by the process of proton pumping by complexes I, III, and IV
phosphorylation / dephosphorylation generates ATP from energy stored by the electron transport chain (ETS) consumes NADPH & FADH2
proton pump ultimately coupled to phosphorylation electron transport is driven by the proximity of reduced and oxidized carriers generated by proton pumping
electron transport

complexes I, III, and IV pump protons

coupled to proton pumping ... you don't get one without the other

electrons enter the chain only through NADH dehydrogenase and succinate dehydrogenase

electron transport is driven by the proximity of reduced and oxidized carriers generated by proton pumping

chemiosmotic gradient

maintained in presence of substrate, and in absence of mitochondrial poisoning by chemicals such as cyanide

ATP synthase protons do not reduce O2, which acts as an electron acceptor

ETS accepts energy from carriers in the matrix

the ETS moves electrons because of the chemiosmotic gradient

ATP synthase membrane-bound enzyme at final step in oxidative phosphorylation follows from and is not part of the electron transport chain
ATP synthase activation does not alter the chemiosmotic gradient ETS maintains the gradient at a constant level

ATP synthase activation increases the rate at which energy is removed from the gradient

O2 consumption ATP is not needed for O2 consumption O2 serves as an electron acceptor, so the electron transport chain drives O2 consumption
Adapted from here.

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