Question

Assertion : The predominant site for control ofgene expression in prokaryotes is transcription initiation.
Reason : The activity of RNA polymerase is regulated by accessory proteins, which affect recognition of start sites.
A. If both assertion and reason are true and reason is the correct explanation of assertion
B. If both assertion and reason are true but reason is not the correct explanation of assertion
C. If assertion is true but reason is false
D. if both assertion and reason are false.

Answer 1

Correct Answer - a
(a) In prokaryotes, control of the rate of transcriptional initiation is the predominant site for control of gene expression. In a transcription unit, the activity of RNA polymerase at a given promoter , isin turn turn regulated by interaction with accessory porteins, Which affect its ability its ability to recognise start sites. These regulatory proteins can act both positively (activators) and negatively (repressors).