- Any of various round or long cellular organelles of most eukaryotes that are found outside the nucleus, produce energy for the cell through cellular respiration, and are rich in fats, proteins, and enzymes -- called also chondriosome.
Definition from: Merriam-Webster's Medical Dictionary by Merriam-Webster Inc.
- Parts of a cell where aerobic production (also called cell respiration) takes place.
National Cancer Institute
- Mitochondria are membrane-bound cell organelles (mitochondrion, singular) that generate most of the chemical energy needed to power the cell's biochemical reactions. Chemical energy produced by the mitochondria is stored in a small molecule called adenosine triphosphate (ATP). Mitochondria contain their own small chromosomes. Generally, mitochondria, and therefore mitochondrial DNA, are inherited only from the mother.
Definition from: Talking Glossary of Genetic Terms from the National Human Genome Research Institute
Related discussion in the Handbook
See also Understanding Medical Terminology.