Unit 4 - Ch. 14: Gene Transcription

Question 1

What is transcription?

Answer 1

The process of making RNA from DNA using RNA polymerase.

Question 2

What are the three stages of transcription?

Answer 2

Initiation - polymerase binds promoter
Elongation - polymerase adds nucleotides 5’ –> 3’
Termination - transcription stops at terminator sequence

Question 3

What is the central dogma of genetics?

Answer 3

DNA → RNA → Protein

Question 4

What part of the gene does RNA polymerase bind to?

Answer 4

The promoter

Question 5

What is the function of the terminator?

Answer 5

Signals RNA polymerase to stop transcription

Question 6

What are structural vs. non-structural genes?

Answer 6

Structural = encode proteins via mRNA
Non-structural = make RNAs like rRNA, tRNA.

Question 6

What are the –35 and –10 boxes?

Answer 6

Consensus sequences in bacterial promoters recognized by RNA polymerase

Question 6

What is rho-dependent termination? independent termination?

Answer 6

• Termination using the rho protein to separate RNA from DNA
• Stem-loop in RNA stalls polymerase, followed by weak U-A bonds causing dissociation

Question 7

Which RNA polymerase makes mRNA in eukaryotes?

Answer 7

RNA polymerase II

Question 8

What forms the preinitiation complex (PIC)?

Answer 8

RNA polymerase II + general transcription factors (GTFs)

Question 9

What does the polyA signal do?

Answer 9

Marks the site for cleavage and polyadenylation of mRNA

Question 10

What are the three mRNA modifications in eukaryotes?

Answer 10

5′ capping, splicing, 3′ poly-A tail

Question 11

What is alternative splicing?

Answer 11

One gene produces multiple mRNA isoforms by varying exon combinations

Question 12

What is RNA editing?

Answer 12

Changing the RNA sequence post-transcription (e.g., C → U)