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mitochondrion
[ mahy-tuh-kon-dree-uhn ]
mitochondrion
/ ˌmaɪtəʊˈkɒndrɪən /
noun
- a small spherical or rodlike body, bounded by a double membrane, in the cytoplasm of most cells: contains enzymes responsible for energy production Also calledchondriosome
mitochondrion
/ mī′tə-kŏn′drē-ən /
, Plural mitochondria
- A structure in the cytoplasm of all cells except bacteria in which food molecules (sugars, fatty acids, and amino acids) are broken down in the presence of oxygen and converted to energy in the form of ATP. Mitochondria have an inner and outer membrane. The inner membrane has many twists and folds (called cristae), which increase the surface area available to proteins and their associative reactions. The inner membrane encloses a liquid containing DNA, RNA, small ribosomes, and solutes. The DNA in mitochondria is genetically distinct from that in the cell nucleus, and mitochondria can manufacture some of their own proteins independent of the rest of the cell. Each cell can contain thousands of mitochondria, which move about producing ATP in response to the cell's need for chemical energy. It is thought that mitochondria originated as separate, single-celled organisms that became so symbiotic with their hosts as to be indispensible. Mitochondrial DNA is thus considered a remnant of a past existence as a separate organism.
- See more at cell
mitochondrion
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Notes
Mitochondria probably entered eukaryotes by an act of endosymbiosis, in which one simple cell was absorbed by another.
Mitochondria contain their own DNA. It is by tracing the mitochondrial DNA, which individuals inherit only from their mothers, that genetic linkages are often traced. ( See mitochondrial Eve .)
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Derived Forms
- ˌmitoˈchondrial, adjective
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Word History and Origins
Origin of mitochondrion1
First recorded in 1900–05; mitochondria ( def )
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Word History and Origins
Origin of mitochondrion1
C19: New Latin, from Greek mitos thread + khondrion small grain
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