Split reins are a piece of equipment used for communicating with a horse while it is being ridden. Split reins are actually two separate, individual reins that are used together, with one rein on each side of the horse's neck.
As discussed above, mitochondria are the sites of respiration, and generate chemical energy in the form of ATP by metabolizing sugars, fats, and other chemical fuels with the assistance of molecular oxygen.
Production of energy. ATP Synthesis. The main function of mitochondria is the production of ATP. According to many textbooks: Energy production within cells is the main function of mitochondria. However, some students are told not to state that mitochondria produce or create energy.