Gen511Exam1Key-08

Gen511Exam1Key-08 - 1 Name GDCB 511 Exam I 100 Points 1(10...

Info iconThis preview shows pages 1–3. Sign up to view the full content.

View Full Document Right Arrow Icon
Name: GDCB 511 Exam I, 2-4-08 100 Points 1. (10 points) How does σ factor in the prokaryotic RNA polymerase complex (a) recognize the promoter? and (b) help melt the promoter at initiation site? -recognizes promoters by binding -35 box and -10 box of the core promoter; -melts DNA in promoters to initiate transcription; three aromatic residues from σ are implicated in melting the DNA by substituting for basepairs. 2. (10 points) It’s proposed that of α subunit in the prokaryotic RNA polymerase complex functions to promote transcription by binding to UP element. Propose two experiments to test the hypothesis. Perform in vitro transcription experiments: (1) Mutate UP element, transcription activation should be abolished; (2) Mutate α subunit, transcription activation should be abolished. 1
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
3. (10 points) If you grow E. coli in medium that contains both glucose and lactose, glucose is used first even though lactose is present, why? Draw a model to facilitate your explanation. When there is glucose in the medium, cAMP level is low and CAP is inactive. The lacZ, lacY and lacA genes will not be expressed even though lactose is present. (When there is no glucose, cAMP level rises. cAMP binds to CAP and the complex interacts with the promoter and help recruit RNA polymerase to activate the expression of lacZ, lacY and lacA genes). 4. (10 points) Tryptophan biosynthesis is controlled by both TrpR repressor and
Background image of page 2
Image of page 3
This is the end of the preview. Sign up to access the rest of the document.

This note was uploaded on 03/08/2010 for the course GDCB 511 taught by Professor Yanhaiyin during the Spring '09 term at Iowa State.

Page1 / 5

Gen511Exam1Key-08 - 1 Name GDCB 511 Exam I 100 Points 1(10...

This preview shows document pages 1 - 3. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online