Part of a mammalian cell culture cell, coloured transmission electron micrograph (TEM). A number of subcellular organelles can be seen including part of the nucleus (green) which contains DNA, the Golgi complex (purple) which has a number of functions including the modification and sorting of proteins for secretion, smooth and rough endoplasmic reticulum (cyan) which produce and transport proteins within the cell and mitochondria (brown) which take in nutrients from the cell and convert it into energy. Magnification: x18000 when printed at 10cm wide.