Mitochondrial matrix

1 Outer membraneIn the mitochondrion, the matrix is the space within the inner membrane. The word 'matrix' stems from the fact that this space is viscous, compared to the relatively aqueous cytoplasm. The mitochondrial matrix contains the mitochondria's DNA, ribosomes, soluble enzymes, small organic molecules, nucleotide cofactors, and inorganic ions. The enzymes in the matrix facilitate reactions responsible for the production of ATP, such as the citric acid cycle, oxidative phosphorylation, oxidation of pyruvate and the beta oxidation of fatty acids. In the mitochondrion, the matrix is the space within the inner membrane. The word 'matrix' stems from the fact that this space is viscous, compared to the relatively aqueous cytoplasm. The mitochondrial matrix contains the mitochondria's DNA, ribosomes, soluble enzymes, small organic molecules, nucleotide cofactors, and inorganic ions. The enzymes in the matrix facilitate reactions responsible for the production of ATP, such as the citric acid cycle, oxidative phosphorylation, oxidation of pyruvate and the beta oxidation of fatty acids. The composition of the matrix based on its structures and contents produce an environment that allows the anabolic and catabolic pathways to proceed favorably for. The electron transport chain and enzymes in the matrix play a large role in the citric acid cycle and oxidative phosphorylation. The citric acid cycle produces NADH and FADH2 through oxidation that will be reduced in oxidative phosphorylation to produce ATP. The cytosolic, intermembrane space, compartment has a water content of 3.8 μl/mg protein, while the mitochondrial matrix 0.8 μl/mg protein. It is not known how mitochondria maintain osmotic balance across the inner mitochondrial membrane, although the membrane contains aquaporins that are believed to be conduits for regulated water transport. Mitochondrial matrix has a pH of about 7.8, which is higher than the pH of the inner membrane of the mitochondria, which is around 7.0-7.4. Mitochondrial DNA was discovered by Nash and Margit in 1963. One to many double stranded mainly circular DNA is present in mitochondrial matrix. Mitochondrial DNA is 1% of total DNA of a cell. It is rich in Guanine and Cytosine content. Mitochondria of mammals have 55s ribosomes. The matrix is host to a wide variety of metabolites involved in processes within the matrix. The citric acid cycle involves acyl-CoA, Pyruvate, acetyl-CoA, citrate, isocitrate, α-Ketoglutarate, succinyl-CoA, fumarate, Succinate, L-Malate, and Oxaloacetate. The Urea Cycle makes use of L-Ornithine, Carbamoyl Phosphate, and L-Citrulline. The electron transport chain oxidizes coenzymes NADH, FADH2. Protein synthesis makes use of mitochondrial DNA, RNA, and tRNA. Regulation of processes makes use of ions(Ca2+/K+/Mg+). Additional metabolites present in the matrix are CO2, H2O, O2, ATP, ADP, and Pi. Enzymes from processes that take place in the matrix. The Citric Acid Cycle is facilitated by Pyruvate dehydrogenase, Citrate synthase, Aconitase, Isocitrate dehydrogenase, α-ketoglutarate dehydrogenase, Succinyl-CoA Synthetase, Fumarase, and Malate dehydrogenase. The Urea Cycle is facilitated by Carbamoyl phosphate synthetase I and Ornithine transcarbamylase. β-Oxidation uses pyruvate carboxylase, Acyl-CoA dehydrogenase, and ?-Ketothiolase. Amino acid production is facilitated by transaminases. 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 Protein complex I (NADH:Coenzyme Q Oxidoreductase), protein complex II (Succinate:Coenzyme Q Oxidoreductase), protein complex III (Coenzyme Q: Cytochrome C Oxidoreductase), and protein complex IV (Cytochrome C Oxidase). 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. 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, iso-citrate dehydrogenase, alpha-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.