Ribosome protein production, artwork. Ribosomes are cellular macromolecules that bind to and move along strands of messenger ribonucleic acid (mRNA), using it as a template to produce proteins. This is a bacterial ribosome (centre) and consists of a large subunit (pink), a small subunit made up of RNA (orange) and protein (brown). Also seen here is transfer RNA (tRNA, yellow), mRNA (green), and EF-Tu elongation factor (blue).