Question

What statement is FALSE?

A. Sigma 54 is very unusual since it can bind the promoter in the absence of RNAP core.

B. Sigma 54 activates the constitutive promoter of the nitrogen starvation gene glnA.

C. Sigma 54 does not have region 1.1.

D. Some NIF genes have dual promoters, which can be turned on either by sigma 70 or sigma 54.

Answer 1

Statement B is false; Sigma 54 typically activates enhancer-dependent promoters and not the constitutive promoter of the nitrogen starvation gene glnA.

Step-by-step explanation:

To answer the student's question regarding sigma factors associated with RNA polymerase in bacteria, we must identify which statement about Sigma 54 is false.

• Sigma 54 is a sigma factor that can indeed bind the promoter in the absence of RNAP core, making statement A true.
• Sigma 54 also activates the enhancer-dependent promoters rather than the constitutive promoters, suggesting statement B is likely the false one.
• It's true that Sigma 54 differs structurally from other sigma factors and does not have region 1.1, making statement C true.
• Regarding the nitrogen fixation (NIF) genes, they can indeed have dual promoters that are recognized by sigma 70 or Sigma 54, so statement D is true.

Based on this evaluation, statement B is the false statement because Sigma 54 typically does not activate constitutive promoters such as that of the nitrogen starvation gene glnA, but rather enhancer-dependent promoters.