Which statement best describes the role of the eubacterial RNA polymerase sigma

Which statement best describes the role of the eubacterial RNA polymerase sigma factor?
A.  Sigma factor allows assembly of RNA polymerase.
B.  Sigma factor is responsible for catalyzing the formation of phosphodiester bonds during RNA polymerization.
C.  Sigma factor shuttles cytoplasmic RNA polymerase to promoter sequences.
D.  Sigma factor increases the affinity of RNA polymerase for promoter sequences.
E.  Sigma factor actively removes core enzyme from DNA and attaches it to a promoter.


What role do the alpha subunits of RNA polymerase play in promoter binding?
A.  They bind to UP elements.
B.  They bind to both the –10 and –35 elements.
C.  They bind only to the –35 element.
D.  They bind to the startpoint.
E.  They bind only to the –10 element.


What is the role of DNA gyrase in transcription?
A.  It assists in the formation of termination hairpin structures.
B.  It melts the DNA duplex to form the transcription bubble.
C.  It removes the positive supercoils generated ahead of RNA polymerase.
D.  It breaks the hydrogen bonds between DNA and RNA during transcription termination.
E.  It removes the negative supercoils generated behind RNA polymerase.