Mitochondria are an organelle that is found in large numbers in most cells. They are found where the biochemical processes of respiration and energy production occur. Mitochondria have a double membrane in which the inner layer is folded inward to make multiple layers.
The main function of mitochondria is to convert energy from food molecules to energy that the cell can actually put to use. In this regard mitochondria have a really important function within a cell. This is done through respiration. The mitochondria also regulate cellular metabolism. Energy is produced both through cellular respiration and cellular metabolism.