Which statement is true about transcription in prokaryotes and eukaryotes?

• A. In prokaryotes, transcription occurs in the nucleus.
• B. In prokaryotes, transcription occurs in the cytoplasm and transcripts can be polycistronic.
• C. In eukaryotes, transcription occurs in the nucleus and translation in the cytoplasm.
• D. In eukaryotes, transcription and translation occur simultaneously.

Answer: (C)

In eukaryotic cells, transcription happens inside the nucleus where the DNA is housed, and the RNA must be processed (capping, splicing, polyadenylation) before it’s exported to the cytoplasm for translation by ribosomes. This spatial separation ensures a regulatory step between transcription and translation and prevents them from occurring at the same time. That makes the statement about transcription in the nucleus and translation in the cytoplasm true.

Prokaryotes lack a nucleus, so transcription takes place in the cytoplasm and mRNAs can be immediately translated; their transcripts are often polycistronic, meaning a single RNA can encode multiple proteins. The idea that transcription and translation occur simultaneously in eukaryotes is incorrect because the nuclear boundary prevents this coupling.