The cells that contain the most mitochondria are the fat and muscle cells. These types of cells perform a variety of functions and require an abundant supply of energy, which is provided by the breakdown of adenosine triphosphate, or ATP, found in the mitochondria.
Cells are the fundamental units of every living organism, which come in a variety of types, shapes and sizes. In most multicellular organisms, the cells are compartmentalized into structures called organelles, which carry out highly specialized functions. These organelles include the plasma membranes, cytoplasm, nuclei, Golgi complexes, channels or pores, endoplasmic reticula, ribosomes, chloroplasts, vesicles, peroxisomes, vacuoles, cell walls, centrioles, lysosomes, cytoskeletons and mitochondria. Considered to be the "power houses" or "energy factories" of the cell, mitochondria are present in both animal and plant cells.
The human body is composed of around 200 cellular types. The majority of these cells are living but those cells found in the hair, nails and some parts of the teeth and bone are non-living. Living animal cells generally contain an estimated 1,000 to 2,000 mitochondria.
Energy production, in the form of ATP molecules, occur in the mitochondria. These high-energy molecules are generated through a series of biochemical reactions known as respiration. Fat cells found in fatty tissues have many mitochondria because they are used as primary storage for excess energy. Muscle cells, which are responsible for bodily movement, also contain an abundant amount of mitochondria.