Mitochondrion. Coloured transmission electron micrograph (TEM) of mitochondria (bluegreen) in heart muscle. Mitochondria are organelles found in the cytoplasm of eukaryotic cells. They oxidise sugar and fats to produce energy. Mitochondria have two membranes (blue), a smooth outer membrane and a folded inner membrane. The folds of the inner membrane are called cristae, and it is here that the chemical reactions to produce energy take place. Magnification: 16,200x when printed 10 centimetres tall.
