Dictionary of Human Evolution and Biology

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Membrane-bound organelle, hundreds of which are present in the cytoplasm of all cells of higher organisms; mitochondria are sites of energy production within cells (respiration) via ATP synthesis. Both because of this high-energy respiratory environment in which mutagens are abundant (see free oxygen radicals), and because they lack the sophisticated repair molecules available to nuclear DNA, mutations occur at a high and seemingly constant rate, and these can be used as a molecular clock. Mitochondria are semiautonomous and able to replicate themselves independently of nuclear mitosis or meiosis. Although their ribosome structure and translation mechanism is unique, they rely on many mRNAs that are imported from the nucleus. Aka chondriosome.

See mitochondrial inheritance, the endosymbiosis theory, and cellular respiration.

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