Mitochondrion is rod like organelle in the cytoplasm of all eukaryotic cells. The number of mitochondria in a cell is variable and ranges from one to ten thousand depending upon the cells’ function. It converts energy to a usable form, so the mitochondrion is considered to be the power house or power generator of the cell.
This shape of mitochondrion may be spherical, elongated or cylindrical in most of the animal and plant cells. The size varies depending upon the physiological conditions of the cells. Mitochondrion is double membrane bound organelle. Outer membrane is smooth while the inner membrane folds and doubles in on itself to form incomplete partitions called crystal. A small space known as inter-membranous space separates the outer membrane from the inner membrane. The crystal increases the surface area available for chemical reactions that trap usable energy for the cell. Inner membrane contains a gel like fluid the mitochondrial matrix where the inner membrane folding the crustae extends.
The matrix contains ribosomes, circular DNA, enzymes and coenzymes in addition to other substances.
Mitochondria are self replicating organelle due to the presence of its own DNA and ribosomes. It replicates when a cell needs to produce more energy.
Mitochondria are seen to be in constant motion in living cells. Mitochondria are the centre of aerobic respiration. Interior of Mitochondrion contains fluid like organic matrix with a number of chemical compounds in it.
On the cristae are located enzymes and coenzymes by means of which carbohydrates (starch), fatty acids, lipids and amino acids (proteins) are metabolized to CO2 and H2O. Energy in the form of ATP is release in this process which is stored within mitochondria. Adenosine triphosphate (ATP) is energy rich compound and it provides energy to the cells of organs for various activities. Hence mitochondria are known as “Power house of cell” where energy is stored and released wherever and whenever required by a living body. Mitochondria have semiautonomous existence in the cell. They have their own DNA that directs production of some of their component proteins and they can divide in half and thus reproduce independently of cells normal cell division cycle.
Mitochondria are passed to an animal only by mother. Since mitochondria are present in eggs but not in the part of the sperm that enters the egg. Thus people can trace their mitochondria back to their mothers and grand mothers.
Functions: Mitochondrion is the centre of cells respiratory and metabolic activity where food is oxidized to carbon dioxide and water through kerb’s cycle and Electron transport chain. During these processes, production of energy in the form of ATP (adenosine triphosphate) also results. Therefore they are called “Power house of the cell”.
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