RR2

Question 1

What is the major regulator of gene expression?

Answer 1

Transcriptional Control

Question 2

What is an overview of transcription?

Answer 2

(RNA copies DNA)

A DNA double helix denatures and one strand acts as a template. There are rNTPs base-pair with bases in template strand. RNA polymerase joins with rNTPs 5’ to 3’. Polymerization is energetically favoured because there are high-energy bonds between alpha and beta phosphates that are replaced by lower energy phosphodiester bond. When base pairing takes place, it will ratchet forward to next nucleotide. Coding sequences will give rise to mRNA usually down stream of transcription site.

Question 3

Which stage of transcription is the rate limiting step?

Answer 3

Initiation

Question 4

What happens in the initiation stage of transcription?

Answer 4

Polymerase binds to promoter sequence, denatures DNA and catalyzes 1st phosphodiester linkage.