Describe the structure and function of mitochondria. How can the structure of the mitochondrial membrane affect the metabolism of the organelle?
Through the break down of food-stuffs, mitochondria release energy to the cell in the form of ATP and, thus, make possible all the life activities of the cell that require energy. Mitochondria have a double-layered membrane. Whereas the outer membrane of a mitochondrion is smooth, the inner membrane has many folds called cristae. The cristae are lined by respiratory assemblies, suborganelles containing the enzymes that break down food-stuffs and generate ATP. In general, cells that have high energy needs have more mitochondria, and, in turn, their mitochondria have more cristae and, thus, more respiratory assemblies. The membrane of the mitochondria, made from a mosaic of proteins and lipids, is differentially permeable, allowing some compounds to pass through while preventing others from doing so. A change in the concentration of a chemical in the cytoplasm can cause a change in the mitochondrial membranes' permeability and, as a consequence, can affect the rate of chemical reaction in the mitochondria. Thus, factors that affect the permeability of a mitochondrion's
membrane also play a part in regulating mitochondrial metabolism.
