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[mahy-tuh-kon-dree-uh n] /ˌmaɪ təˈkɒn dri ən/
noun, plural mitochondria
[mahy-tuh-kon-dree-uh] /ˌmaɪ təˈkɒn dri ə/ (Show IPA).
Cell Biology.
an organelle in the cytoplasm of cells that functions in energy production.
Origin of mitochondrion
1900-05; < Greek míto(s) thread + chóndrion small grain, equivalent to chóndr(os) grain, corn + -ion diminutive suffix
Related forms
mitochondrial, adjective Unabridged
Based on the Random House Dictionary, © Random House, Inc. 2018.
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British Dictionary definitions for mitochondrion


noun (pl) -dria (-drɪə)
a small spherical or rodlike body, bounded by a double membrane, in the cytoplasm of most cells: contains enzymes responsible for energy production Also called chondriosome
Derived Forms
mitochondrial, adjective
Word Origin
C19: New Latin, from Greek mitos thread + khondrion small grain
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition
© William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins
Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012
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Word Origin and History for mitochondrion

singular of mitochondria.

Online Etymology Dictionary, © 2010 Douglas Harper
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mitochondrion in Medicine

mitochondrion mi·to·chon·dri·on (mī'tə-kŏn'drē-ən)
n. pl. mi·to·chon·dri·a (-drē-ə)
A spherical or elongated organelle in the cytoplasm of nearly all eukaryotic cells, containing genetic material and many enzymes important for cell metabolism, including those responsible for the conversion of food to usable energy. It consists of two membranes: an outer smooth membrane and an inner membrane arranged to form cristae.

mi'to·chon'dri·al (-drē-əl) adj.
The American Heritage® Stedman's Medical Dictionary
Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.
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mitochondrion in Science
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, cellular respiration.

The American Heritage® Science Dictionary
Copyright © 2002. Published by Houghton Mifflin. All rights reserved.
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mitochondrion in Culture
mitochondrion [(meye-tuh-kon-dree-uhn)]

The cell organelle where much of cellular respiration takes place; the “power plant” of the cell.

Note: Mitochondria probably entered eukaryotes by an act of endosymbiosis, in which one simple cell was absorbed by another.
Note: Mitochondria contain their own DNA. It is by tracing the mitochondrial DNA, which individuals inherit only from their mothers, that genetic linkeages are often traced. (See mitochondrial Eve.)

A cutaway view.

The New Dictionary of Cultural Literacy, Third Edition
Copyright © 2005 by Houghton Mifflin Company.
Published by Houghton Mifflin Company. All rights reserved.
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