Trp Operon (14.1)

Question 1

How is expression of the trp operon regulated? (2 ways)

Answer 1

Negative regulation (using a co-repressor)
Attenuation

Question 2

When tryptophan is present, the trp repressor ____ to the operator sequence
When bound to the operator sequence, the transcription of the trp operon is ______
In this system, tryptophan acts as a _______
The regulation of the trp operon by trpR is an example of _____ gene regulation

Answer 2

binds; inhibited; corepressor; negative

Question 3

Attenuation structure

Answer 3

3 and 4 form

Question 4

Anti termination structure

Answer 4

2 and 3 form

Question 5

When tryptophan levels are high

Answer 5

Transcription terminates
Rho Independent
Promotes the formation of the attenuation structure that acts as a transcription termination sequence for RNA polymerase

Question 6

When transcription levels are low

Answer 6

Ribosome is stalled at the trp codons allows the anti attenuation structure to form –> transcription proceeds

Question 7

Positive feedback loop

Answer 7

When the product promotes the expression of creating more of the product

Question 8

Negative feedback loop

Answer 8

when the product blocks the expression of genes creating more of the product