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Study Guide for Exam 4
Chapter 15
1. Operons
A. Define operon,
promoter, operator, inducible and repressible.
B. Where operons
are found (types of organisms)?
C. Describe
the regulation of the lactose operon. Include operator sites, structure of
repressor.
D. What is a
constitutive operator mutant?
E. What is catabolic
repression? How are CAP and cAMP involved?
F. What is the
difference between positive and negative regulation of operons?
2. Describe attenuation
in the tryptophan operon.
A. Definition
of attenuation.
B. Structure
of leader sequence.
C. What happens
in presence of high levels of tryptophan?
D. What happens
during tryptophan starvation?
E. What happens
during starvation for ALL amino acids?
3. Discuss the regulation
of expression in lambda phage. Include:
A. Function
of cro, cI, N, Q
B. Sequence
of events leading to lysogeny.
C. Sequence
of events resulting in lytic cycle.
4. How are heat
shock proteins coordinately turned on?
5. Explain why,
if the organization of an operon is o A B C, where o is the operator and A,
B and C are genes, there is typically more of gene product A in the cell than
gene product C.
Chapter 16
1. Compare and contrast
the organization of eukaryotic vs. prokaryotic cells in terms of synthesis
of DNA, RNA and protein. Discuss how these differences impact regulation
of gene expression. This should be a big picture of differences; dont
go into details!!
2. Describe how
each of the following affects eukaryotic transcription:
A. Sigma factors
B. Nucleosomes
C. Enhancers
Chapter 18
1. What is the difference
between a back mutation, intragenic suppression and intergenic suppression?
2. What are transitions?
Transversions?
3. What rare form
of the bases can allow them to base pair incorrectly?
4. Repair: briefly
provide an overview of each of the following types of repair:
A. Photo repair
(UV)
B. Mismatch
repair (methylation)
C. Post-replication
repair (RecA)
5. SOS repair
A. Under what
circumstances does SOS repair occur?
B. What role
does LexA play in SOS repair?
C. What classes
of genes are turned on during SOS repair?
Chapter 19
6. Transposable
elements
A. What is a
transposable element?
B. What is the
structure of an IS element?
C. What is a
composite transposon?
D. What us the
relationship between Ac and Ds elements? Where are they found?
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