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.
mitochondrion - an organelle containing enzymes responsible for producing energy. chondriosome. sarcosome - a large mitochondrion in a striated muscle fiber. cell organ, cell organelle, organelle - a specialized part of a cell; analogous to an organ; the first organelle to be identified was the nucleus.