Why does E.coli have several different sigma factors?
A)They allow different RNA polymerases to bind to the promoters.
B)They allow the different subunits of the RNA polymerase holoenzyme to bind to each other.
C)There is no good reason.They all perform the same function.
D)One is needed to transcribe mRNA.A second is needed to transcribe tRNA.And a third is needed to transcribe rRNA.
E)They allow RNA polymerase to recognize and bind to a different subset of promoters.

Question

Quizplus · Accepted Answer

E. coli has multiple sigma factors to allow for RNA polymerase to recognize and bind to a different subset of promoters. Each sigma factor recognizes a specific promoter sequence and regulates the expression of different genes. This allows the bacterium to respond to changes in its environment by selectively transcribing different sets of genes.

Why Does E.coli Have Several Different Sigma Factors