Transcription

Question 1

What is transcription?

Answer 1

Synthesis of RNA from template DNA

Question 2

What does RNA polymerase do?

Answer 2

Catalyzes transcription.

Question 3

What does transcription require?

Answer 3

template
1. RNA strand synthesized is complementary to template
2. other DNA strand has the same sequence as the RNA
Ribonucleoside triphosphates (ATP, CTP, GTP, and UTP)

Question 4

What are the three steps of RNA synthesis?

Answer 4

Initiation, elongation, termination

Question 5

Describe the components of initiation

Answer 5

A. -35 sequence on the coding strand.
B. -10 sequence “Pribnow box” on the coding strand
C. Recognized by the sigma subunit to facilitate initiation

Question 6

Describe the components of elongation

Answer 6

A. RNA polymerase unwinds a 17 bp segment of DNA resulting in the “open” promoter complex
B. RNA synth can start de novo without needing primer
C. RNA strand 5–> 3’ direction

Question 7

describe termination and what it is caused by

Answer 7

• termination occurs by formation of RNA hairpin from GC stop signal. in mRNA, 4 or more uracils follow the hairpin
• can occur by Rho protein activity