Bacterial gene expression. Illustration showing where the key processes of gene expression occur in bacterial cells. Gene expression is where DNA (deoxyribonucleic acid) is transcribed into RNA (ribonucleic acid), which is then used (translated) to produce proteins. In bacteria and other prokaryotes, both transcription and translation occur in the cytoplasm. A loop of DNA (blue, left) is transcribed to produce mRNA (messenger RNA, purple, centre). A ribosome (blue, right) uses the mRNA to produce polypeptides (red) in protein synthesis. For eukaryotic gene expression, see C023/8866. For this artwork without labels, see C023/8865.