In prokaryotes, how are transcription and translation related?

• A. They occur in separate compartments with transcription in the nucleus.
• B. mRNA undergoes extensive processing before translation.
• C. They are coupled in the cytoplasm, with translation beginning before transcription is completed.
• D. Translation occurs in the nucleus.

Answer: (C)

Prokaryotes couple transcription and translation in the cytoplasm because there is no nucleus to separate these processes. As the RNA polymerase is still synthesizing mRNA, ribosomes can bind the fresh transcript and begin translating right away. This setup lets protein production start almost immediately after a gene is transcribed, which is advantageous for quickly adapting to changing conditions. Additionally, prokaryotic mRNA typically doesn’t undergo extensive processing like splicing or capping, so it’s ready for translation soon after transcription begins. The idea of transcription in a nucleus, translation in a distant compartment, or extensive mRNA processing doesn’t fit prokaryotic cells, where these steps are not separated and processing is minimal.