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.
The main function of mitochondria is to produce energy for the cell. Cells use a special molecule for energy called ATP. ATP stands for adenosine triphosphate. The ATP for the cell is made within the mitochondria. You can think of the mitochondria as the energy factory or power plant of the cell.