Mitochondria

2nd phase of cellular respiration--called TCA cycle or Krebs' cycle. Actually, Glucose is split into two molecules of Pyruvic acid in cytoplasm during first phase of respiration ---called Glycolysis. The pyruvic acid then enters Mitochondriawhere pyruvate oxidation takes place resulting in the formation of Acetyl-coA. This compound is stepwise broken down in the matrix of mitochondria releasing all the energy,i.e 36ATP. It is way mitochondria is called energy house of a cell. Mitochondrial matrix is the site of the citric acid cycle, a part of cellular respiration. It is also the site of electron transport chain * 3 years ago ------------------------------------------------- Inner Mitochondria & Matrix Inside the deepest compartments of the mitochondria is the mitochondrian matrix. It is in the matrix that cellular respiration occurs, where pyruvate (a product of glycolysis in the cytosol) is converted to Carbon Dioxide and water. The matrix is the site of the the citric acid cycle, whereby the electron transport chain is used to setup a proton gradient between the inner and outer membrane of the mitochondria, known as the inter membrane space. The protons in the inter membrane space accumulate to a point that the concentration gradient causes the protons to flow back into the matrix. It is the inner membrane that is studded with the proteins necessary for the electron transport chain, such as the cytochrome electron shuttles. Upon reentering the matrix, the H+ go through ATP synthase, which in turns powers the synthase to phosphorylate adenosine diphosphate (ADP) to adenosine triphosphate (ATP). The ATP can be used later on to be coupled with thermodynamically unfavorable reactions to allow those chemical reactions to proceed. The inner membrane is folded and convoluted which allows for a greater surface area to utulize for the electron transport chain. These convolutions are what make up the cristae. Interestingly enough the matrix of the mitochondria are one of the few locations outside of the nucleus where genetic information can be found in the cell. Mitochondrial DNA is similar in appearance to that of bacterial DNA due to its circular shape. The matrix is also known to house tRNA and ribosomes, which further solidifies the theory that the mitochondria entered the ancestral eukaryotic cell as single celled organism. The matrix is the space enclosed by the inner membrane. It contains about 2/3 of the total protein in a mitochondrion. The matrix is important in the production of ATP with the aid of the ATP synthase contained in the inner membrane. The matrix contains a highly-concentrated mixture of hundreds of enzymes, special mitochondrial ribosomes, tRNA, and several copies of the mitochondrial DNA genome. Of the enzymes, the major functions include oxidation of pyruvate and fatty acids, and the citric acid cycle. Mitochondria have their own genetic material, and the machinery to manufacture their own RNAs and proteins. A published human mitochondrial DNA sequence revealed 16,569 base pairs encoding 37 total genes: 22 tRNA, 2 rRNA, and 13 peptide genes. The 13 mitochondrial peptides in humans are integrated into the inner mitochondrial membrane, along with proteins encoded by genes that reside in the host cell's nucleus. Read more: http://wiki.answers.com/Q/What_is_the_function_of_matrix_in_mitochondria#ixzz1bYvYNqRu http://rpi.edu/dept/bcbp/molbiochem/MBWeb/mb1/part2/oxphos.htm http://www.life.illinois.edu/crofts/bioph354/lect14&15.html http://www.ncbi.nlm.nih.gov/books/NBK26828/