Fig. 2
From: Structure and function of mitochondrial membrane protein complexes
Membrane protein complexes of the respiratory chain. Electron transport complexes I (NADH/ubiquinone oxidoreductase, blue), II (succinate dehydrogenase, pink), III (cytochrome c reductase, orange), IV (cytochrome c oxidase, green) and the mitochondrial ATP synthase (also known as complex V, tan) work together in oxidative phosphorylation to harness energy for the cell. Complexes I, III and IV pump protons across the cristae membrane, creating the proton gradient that drives ATP synthesis. UQ ubiquinol. (Adapted from Davies KA, Daum B. Biochem. Soc. Trans. 2013;41:1227–34.)