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.
It is bounded by two sets of membranes, a smooth outer one and an inner one that is arranged in folds, or cristae, that extend into the interior of the mitochondrion, called the matrix. Mitochondria provide the principal source of cellular energy through oxidative phosphorylation and adenosine triphosphate synthesis. They also contain the enzymes involved with electron transport and the citric acid and fatty acid cycles.
A secondary function of mitochondria is to synthesize proteins for their own use. They work independently, and execute the transcription of DNA to RNA, and translation of RNA to amino acids (the building blocks of protein), without using any components of the cell.