In prokaryotes, control of gene expression usually occurs at the

• A. Splicing of pre-mRNA into mature mRNA.
• B. Post-translational control level.
• C. Transcriptional control level.
• D. All of the above.

Answer: (C)

Verified step by step guidance

1. Understand that gene expression in prokaryotes is primarily controlled at the transcriptional level. This means that the regulation occurs when the DNA is transcribed into RNA.
2. Recognize that prokaryotes do not have a nucleus, and their DNA is not separated from the rest of the cell. This allows transcription and translation to occur almost simultaneously.
3. Note that splicing of pre-mRNA into mature mRNA is a process that occurs in eukaryotes, not prokaryotes, because prokaryotes do not have introns that need to be spliced out.
4. Post-translational control involves modifications after a protein has been synthesized, which is less common in prokaryotes compared to transcriptional control.
5. Conclude that the primary level of gene expression control in prokaryotes is at the transcriptional level, where the synthesis of RNA from DNA is regulated.