pyruvate carboxylase, acyl-CoA dehydrogenase, and β-ketothiolase. Amino acid production is facilitated by transaminases. Amino acid metabolism is mediated by proteases, such as presequence protease. Inner membrane components The inner membrane is a phospholipid bilayer that contains the complexes of oxidative phosphorylation. which contains the electron transport chain that is found on the cristae of the inner membrane and consists of four protein complexes and ATP synthase. These complexes are complex I (NADH:coenzyme Q oxidoreductase), complex II (succinate:coenzyme Q oxidoreductase), complex III (coenzyme Q: cytochrome c oxidoreductase), and complex IV (cytochrome c oxidase). Inner membrane control over matrix composition The electron transport chain is responsible for establishing a pH and electrochemical gradient that facilitates the production of ATP through the pumping of protons. The gradient also provides control of the concentration of ions such as Ca2+ driven by the mitochondrial membrane potential. The membrane only allows nonpolar molecules such as CO2 and O2 and small non charged polar molecules such as H2O to enter the matrix. Molecules enter and exit the mitochondrial matrix through transport proteins and ion transporters. Molecules are then able to leave the mitochondria through porin. These attributed characteristics allow for control over concentrations of ions and metabolites necessary for regulation and determines the rate of ATP production. Processes Citric acid cycle Following glycolysis, the citric acid cycle is activated by the production of acetyl-CoA. The oxidation of pyruvate by pyruvate dehydrogenase in the matrix produces CO2, acetyl-CoA, and NADH. Beta oxidation of fatty acids serves as an alternate catabolic pathway that produces acetyl-CoA, NADH, and FADH2. The production of acetyl-CoA begins the citric acid cycle while the co-enzymes produced are used in the electron transport chain. All of the enzymes for the citric acid cycle are in the matrix (e.g. citrate synthase, isocitrate dehydrogenase, α-ketoglutarate dehydrogenase, fumarase, and malate dehydrogenase) except for succinate dehydrogenase which is on the inner membrane and is part of protein complex II in the electron transport chain. The cycle produces coenzymes NADH and FADH2 through the oxidation of carbons in two cycles. The oxidation of NADH and FADH2 produces GTP from succinyl-CoA synthetase. Oxidative phosphorylation NADH and FADH2 are produced in the matrix or transported in through porin and transport proteins in order to undergo oxidation through oxidative phosphorylation. NADH and FADH2 undergo oxidation in the electron transport chain by transferring an electrons to regenerate NAD+ and FAD. Protons are pulled into