mitochondrion

[mahy-tuh-kon-dree-uhn]

noun

Cell Biology.

1. the singular of mitochondria.

mitochondrion

/ ˌmaɪtəʊˈkɒndrɪən /

noun

1. Also called: chondriosome. a small spherical or rodlike body, bounded by a double membrane, in the cytoplasm of most cells: contains enzymes responsible for energy production

mitochondrion

plural

mitochondria 

1. 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.

2. See more at cell cellular respiration

mitochondrion

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

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.)

Other Word Forms

• mitochondrial adjective

Word History and Origins

Origin of mitochondrion¹

First recorded in 1900–05; mitochondria ( def. )

Word History and Origins

Origin of mitochondrion¹

C19: New Latin, from Greek mitos thread + khondrion small grain

Example Sentences

A newly identified kind of DNA damage inside mitochondria, the small structures that supply cells with energy, may help explain how the body detects and reacts to stress.

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A key reason is the shrinking number of mitochondria, the small, organ-like structures inside cells that supply most of the energy a cell uses.

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The team pinpointed a protein that enables cancer cells to alter the shape of their mitochondria, the structures that generate cellular energy.

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The team is looking at how frequencies of red light can change the mitochondria inside the brain to improve focus.

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"We were stunned -- not only did kidney function stay normal, but the mitochondria were unscathed," Summers says.

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