The action of a bacterial gene in protein synthesis: false-colour transmission electron micrograph (TEM) of a structural gene from the bacterium Eschericia coli, showing the coupled transcription of DNA into messenger RNA (mRNA) molecules and the translation of this messenger code into protein molecules. The DNA fibre runs down the image (in yellow) from top left, with numerous ribosomes (in red) attached to each mRNA chain. The longer chains (called polysomes) are furthest from the point of gene origin (at top of image). Magnification: x32,600 at 6x4.5cm size.