Question

How does the direction of the promoter affect mRNA transcription, considering RNA polymerase always extends mRNA from 5' to 3'?

a. Promoters dictate the direction of mRNA transcription, contrary to the 5' to 3' extension.
b. mRNA transcription always extends from 5' to 3', independent of promoter direction.
c. Promoter direction influences the initiation of mRNA transcription.
d. mRNA transcription initiates randomly regardless of promoter direction.

Answer 1

The direction of the promoter is crucial for the initiation of mRNA transcription because it determines where RNA polymerase binds and starts synthesizing mRNA.

Step-by-step explanation:

How does the direction of the promoter affect mRNA transcription, considering RNA polymerase always extends mRNA from 5' to 3'? The correct answer is c. Promoter direction influences the initiation of mRNA transcription. This is because the promoter identifies the correct segment of DNA to transcribe and determines the direction RNA polymerase will take as it synthesizes an mRNA molecule. Transcription starts at the promoter site and proceeds in the 5' to 3' direction along the template strand of DNA, which is read in the 3' to 5' direction. The promoter must be oriented correctly for RNA polymerase to bind and initiate transcription properly.