Mitochondria generate chemical energy, similar to the type of energy you get from a battery. The energy made by the mitochondria is in the form of a chemical called adenosine triphosphate or ATP for short. ATP is an energy currency that every cell in our body can use and it keeps us alive. The machinery that the mitochondria use to make ATP is called the electron transport chain. This chain is made up of 4 complexes which are groups of proteins that work together to carry out their function, the 5th complex is responsible for the final step of the energy generation. It is found in the inner mitochondrial membrane and parts of the first, third, fourth and fifth complexes are coded for by the mitochondrial DNA. In order for energy to be generated several steps have to occur.