Mitochondria are structures within cells that convert the energy from food into a form that cells can use. Mitochondrial DNA contains 37 genes, all of which are essential for normal mitochondrial function. Thirteen of these genes provide instructions for making enzymes involved in oxidative phosphorylation.
They were individual organisms that were assimilated into a larger cell.
Explanation:
It's how simple cells became complex cells. Also, the cell and the mitochondria share a symbiotic relationship: the cell provides a safe space for the mitochondria to live, and the mitochondria provide energy to the cell in the form of ATP.
