Control of gene expression in prokaryotes part 2

Question 1

Define CIII (including relative location)

Answer 1

• Factor that maintains CII,
• Required for lysogenic pathway
• Found just past tL

Question 2

Define N (including relative location)

Answer 2

• Turns on delayed early
• required for both lysogeny and lysis
• product found in PLOL

Question 3

Define cI (including relative location)

Answer 3

• Repressor that facilitates the lysogenic pathway

- Product found past PRM

Question 4

Define cro (including relative location)

Answer 4

• turns off repressor (cI)
• facilitates the lytic cycle
• product of PROR

Question 5

Define cII (including relative location)

Answer 5

• Turns on cI
• Required for the lysogenic pathway
• found past tR

Question 6

Define Q (including relative location)

Answer 6

• Turns on late lytic cycle

- Found far into the plasmid away from Promoter

Question 7

What two genes are transcribed in the immediate early phase?

Answer 7

cro and N

Question 8

What genes are transcribed in the delayed early phase

Answer 8

Q, cii and ciii

9 other miscellaneous genes

Question 9

What occurs in the late stage of the lytic pathway?

Answer 9

Transcription occurs at PR (between Q and S) and pQ allows it to continue to all late genes

Question 10

What are the three parts of the c1 repressor?

Answer 10

1. Homo-Dimerization portion
2. Connector
3. DNA-binding

Question 11

How does c1 inhibit Cro and N while activating its own transcription?

Answer 11

It binds to operator regions 1 and 2, while facilitating the binding of RNA pol to region 3.

Question 12

Define cooperative binding

Answer 12

A first site is filled up first, which causes a second site to become more attractive for binding.

Question 13

What are two ways that transcription stimulates lysogeny at PRE

Answer 13

1. It allows initial expression of the C1 repressor

2. It produces anti-sense RNA for cro