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

MitochondrionA cutaway view.
- 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.)