Figure 2.

Mitochondrial physiology. Acetyl-CoA enters the mitochondrion via pyruvate or fatty acids. Pyruvate is imported through the mitochondrial inner membrane by the pyruvate dehydrogenase complex (PDC), and is oxidatively decarboxylated to produce acetyl-CoA. Fatty acids form acyl-CoA in the cytosol, and are transported into mitochondrion through carnitine (CAT) for β-oxidation. Acyl-CoA enters the citric acid cycle, and generates NADH and FADH2 (co-enzymes used in the electron transport chain) to produce ATP.