Ribosome and protein synthesis. Diagram showing protein synthesis in cells (translation). Messenger ribonucleic acid (mRNA, blue with coloured nucleotides) is read by a ribosome (pink). The molecules of transfer RNA (tRNA, key-shaped) each bring an amino acid (orange dot) to bind to the ribosome's protein synthesis site. The amino acid added is determined by the three-nucleotide coding (codon) on the mRNA, which matches up with the corresponding anti-codon on the tRNA molecule. This successive addition of amino acids results in a growing polypeptide (protein) chain (orange spheres). For this artwork without labels, see C029/3019.