Caption

Distal fragment of a translation unit from a midge (Chironomus sp.) salivary gland cell, coloured transmission electron micrograph (TEM). Translation is the synthesis of proteins from a messenger ribonucleic acid (RNA) strand. Ribosomes (blue) attach to the mRNA strand (pink) and read its code. A transfer RNA (tRNA) molecule carrying an amino acid corresponding to the code binds to the ribosome. When the tRNA dissociates it leaves the amino acid, and the ribosome moves onto the next bases. As the ribosome moves along the mRNA a protein (green) grows from the ribosome. Magnification: x72,500 when printed at 10 centimetres wide.