Matrix (biology)
From Wikipedia, the free encyclopedia
In biology, matrix (plural: matrices) is the material between animal or plant cells, the material (or tissue) in which more specialized structures are embedded, and a specific part of the mitochondrion that is the site of oxidation of organic molecules. The internal structure of connective tissues is an extracellular matrix. Finger nails and toenails grow from matrices.
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[edit] Matrix (medium)
A matrix is also a medium in which bacteria are grown (cultured). For instance, a Petri dish of agar may be the matrix for culturing a sample swabbed from a patient's throat.
[edit] Mitochondrial matrix
In the mitochondrion, the matrix contains soluble enzymes that catalyze the oxidation of pyruvate and other small organic molecules.
The matrix of the mitochondria also contains the mitochondria's DNA and ribosomes. The word "matrix" stems from the fact that this space is very viscous, compared to the very aqueous cytoplasm. The molarity of water in the cytosol is typically about 55 molar, while in the mitochondrial matrix it is approximately 7 molar. Mitochondria maintain a very strictly regulated composition of their matrix, assisted by a very impermeable inner mitochondrial membrane. Notably though, mitochondria do contain conduits for regulated water transport, called aquaporins. Mitochondria contain specifically aquaporin 9.
[edit] Citric acid cycle
The location of the Citric acid cycle (or Kreb cycle or TCA cycle) is within the mitochondrial matrix. In this cycle, pyruvic acid generated from glycolysis is converted into acetyl coenzyme A (acetyl CoA) by losing a Carbon Dioxide molecule. It then combines with oxaloacetic acid to form citric acid, a six-carbon molecule. In total, it loses 2 CO2 molecules and 4 electrons, of which 3 are accepted by NAD+ to reduce it to NADH, and the last electron accepted by FAD+ to reduce to FADH2 in redox reactions. In the end, it regenerates oxaloacetic acid to continue Krebs cycle. In addition, a single ATP molecule is created from the combination of ADP and a phosphate group.
Since 2 pyruvic acid molecules are formed by glycolysis, each time a cell undergoes glycolysis two turns of the Citric acid cycle will occur. That means that the Krebs Cycle produces a total of 6 NADH, 2 FADH2, and 2 ATP molecules.
[edit] Electron Transport Chain
The electron transport chain is located in the cristae of the inner mitochondrial membrane. The NADH and FADH2 produced by the Krebs cycle in the matrix release a proton and electron to regenerate NAD+ and FAD+. The proton is pulled into the intermembrane space by the energy of the electrons going through the electron transport chain. The electron is finally accepted by oxygen in the matrix. The protons return to the mitochondrial matrix through the process of chemiosmosis through the protein ATP synthase.
[edit] Bone Matrix
Bone is a form of connective tissue found in the body and has a storage area, or osteon region, also called matrix that allows mineral salts such as calcium to be stored.
