Transcription and translation occur simultaneously in prokaryotes.
Explanation:
Prokaryotes lack membrane-bound organelles and therefore, do not have a nucleus. Transcription and translation occur in the cytoplasm. As soon as the required length of mRNA is being formed, ribosomes join it and start the process of translation. Prokaryotic genes lack introns. The primary transcript formed by transcription in prokaryotes does not undergo splicing.
On the other hand, the process of transcription occurs in the nucleus in eukaryotes while translation occurs in the cytoplasm. The primary transcript formed by transcription in eukaryotes undergoes modifications to remove introns and to add a poly-A tail and 5' cap. Post-transcriptional modifications and spatial separation of two processes in eukaryotes result in slower translation than prokaryotes.
