mitochondrion
Americannoun
noun
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.
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See more at cell cellular respiration
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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
Etymology
Origin of mitochondrion
First recorded in 1900–05; mitochondria ( def. )
Example Sentences
Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.
This included reduced loss of synapses and less structural and functional damage to mitochondria, the powerhouses of the cell.
From Science Daily
These include activating immune cells, increasing oxidative stress, disrupting the blood-brain barrier, interfering with mitochondria, and damaging neurons.
From Science Daily
A new study from Yale researchers, published in Nature Metabolism, reveals that CoA is transported into mitochondria through specific cellular mechanisms.
From Science Daily
Many of these enzymes are typically known for producing energy in mitochondria, yet researchers discovered them sitting on chromatin inside the cell nucleus.
From Science Daily
The study shows that plant mitochondria can draw molecular oxygen away from chloroplasts.
From Science Daily
Definitions and idiom definitions from Dictionary.com Unabridged, based on the Random House Unabridged Dictionary, © Random House, Inc. 2023
Idioms from The American Heritage® Idioms Dictionary copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.