Mitochondria are the site of oxidative phosphorylation in all eukaryotic cells and are the main centres of ATP production. Plant mitochondria have a highly branched ETC that provides flexibility for oxidation of cytosolic and matrix NAD(P)H. In addition to the universal cytochrome pathway found in many organisms, plants have matrix-facing and cytosol-facing non-phosphorylating NAD(P)H dehydrogenases which bypass Complex I and the matrix-facing Alternative oxidase (AOX) which bypasses Complexes III and IV. The alternative pathways are non-proton pumping and allow NAD(P)H oxidation with varying...