In prokaryotes, where do transcription and translation both occur?

In prokaryotes, transcription and translation both occur in the cytoplasm. This is a key distinction between prokaryotic and eukaryotic cells. Prokaryotes lack a defined nucleus, which means that the processes of transcription (the synthesis of mRNA from a DNA template) and translation (the synthesis of proteins from mRNA) can occur simultaneously in the cytoplasm.

When a gene is transcribed into mRNA, ribosomes can begin translating that mRNA into protein even before transcription has been completed. This is efficient for prokaryotic organisms, allowing them to quickly respond to environmental changes by rapidly producing the needed proteins.

In contrast, eukaryotic cells separate these processes: transcription occurs in the nucleus while translation takes place in the cytoplasm. This spatial separation allows for additional processing of mRNA, such as splicing and modification, before it is translated.

Thus, recognizing that prokaryotic cells perform both transcription and translation in the same location is essential for understanding their cellular mechanics and efficiency.