Minor differences in the consensus sequence for RNA Polymerase
A) can be exploited to vary the amount of mRNA which is synthesized from that gene.
B) dictate the direction that RNA Pol proceeds from the promoter.
C) dictate whether sigma (s) factor is required.
D) never occur.

Question

Quizplus · Accepted Answer

Minor differences in the consensus sequence for RNA Polymerase can affect the binding affinity of RNA polymerase and transcription factors, leading to variations in the amount of mRNA synthesized from that gene. This can determine the level of gene expression in the cell.

Answer: B 
 The consensus sequence for RNA polymerase determines the direction of transcription from the promoter. A change in the consensus sequence can lead to altered transcription initiation site and therefore, the direction of RNA Pol proceeds.

Answer: C 
 The consensus sequence dictates the specificity of the promoter recognition by sigma factor. Some promoters require specific sigma factors for initiation of transcription, while others do not. Thus, minor differences in the consensus sequence can affect whether sigma factor is required.

Answer: D 
 This statement is incorrect. Minor differences in the consensus sequence can occur naturally or due to mutational changes.

Minor Differences in the Consensus Sequence for RNA Polymerase