Falsecolour transmission electron micrograph of a mitochondrion from an unidentified cell. Mitochondria are the sites of cell respiration; the chemical process which uses molecular oxygen to oxidise sugars & fats in order to produce energy. The energy is stored as adenosine triphosphate (ATP) & is used by the cell to drive chemical reactions such as protein formation. Mitochondria are bound by a double membrane. The inner membrane is folded to produce ingrowths called cristae (seen here as a series of paired, parallel pink lines), which are the sites where the chemical reactions of respiration occur. Mag: x 48,000 at 6x7cm, x 24,000 at 35mm size.