The organelle that provides energy for the cell is mitochondrion. While mitochondria are the primary source of energy in eukaryotic cells, cells can still derive a small amount of energy from other processes like glycolysis.
Mitochondria are not found in all cells; they are only found in those that require energy. Furthermore, some types of cells have many more than one mitochondrion. For example, liver cells often have more than 2,000, but red blood cells have zero. Mitochondria have a bean-like outer shape and has the rare ability of being able to divide independently of the cell. This means that even if a cell is replicated, the mitochondria must divide on their own accord.