Mitochondrion

The mitochondrion (plural: Mitochondria) is a organelle that makes ATP out of Glucose. It makes 38 ATP out of 1 glucose. Later in the game, it can be used to burn heat out of glucose instead of ATP. If the cell has less than 250 ATP and no glucose, it will burn fatty acids instead of Glucose for 108 ATP.

Be warned, Mitochondrion produce Free Radicals that can damage other organelles such as the Nucleus.