Regarding regulation of transcription, which of the following statements is correct?
A) The CAP protein-cAMP complex binds the lac repressor thereby permitting transcription of the lac operon.
B) The lac repressor is a small piece of RNA which binds the operator region of the lac operon.
C) The operator region of the lac operon is less than 150 base pairs in length.
D) The z gene of the lac operon codes for the lac repressor.
E) All of the above.

Question

Quizplus · Accepted Answer

The operator region of the lac operon is typically around 20 base pairs in length, so statement C is the only accurate statement regarding regulation of transcription in this scenario. The other statements contain inaccuracies. Statement A is incorrect because the CAP protein-cAMP complex enhances binding of RNA polymerase to the lac operon promoter, but has no direct effect on the lac repressor. Statement B is incorrect because the lac repressor is a protein, not an RNA molecule. Statement D is incorrect because the lac repressor is encoded by the i gene, not the z gene, of the lac operon.

Regarding Regulation of Transcription, Which of the Following Statements Is