Question 1

What would be the phenotype of an int− $\lambda$mutant?

Accepted Answer

A) The phage would not be able to undergo the lytic cycle, but could lysogenize. 
B) Both lytic and lysogenic pathways would be inactivated. 
C) The phage would be able to enter the lytic cycle, but would not be able to lysogenize. 
D) The phage would be able to lysogenize but would not be able to be induced to resume the lytic cycle. 
E) The cell would build up high levels of $\lambda$repressor, so lysogeny would be maintained. 
A) The phage would not be able to undergo the lytic cycle, but could lysogenize. 
B) Both lytic and lysogenic pathways would be inactivated. 
C) The phage would be able to enter the lytic cycle, but would not be able to lysogenize. 
D) The phage would be able to lysogenize but would not be able to be induced to resume the lytic cycle. 
E) The cell would build up high levels of $\lambda$repressor, so lysogeny would be maintained. C

Question 2

Expression of a(n)________ alters gene transcription in E. coli by activating transcription of specialized heat stress response genes.

Accepted Answer

alternative sigma factor

Question 3

Which structural gene of the lac operon can be mutated without affecting the cell's ability to break down lactose?

Accepted Answer

A) lacZ 
B) lacY 
C) lacA 
D) lacP 
E) lacO 
A) lacZ 
B) lacY 
C) lacA 
D) lacP 
E) lacO C

Question 4

Which of the following can be mutated to result in constitutive expression from the lac operon?

Accepted Answer

A) lacZ and lacP 
B) lacZ and lacI 
C) lacO and lacI 
D) lacO and lacZ 
E) lacI and lacY 
A) lacZ and lacP 
B) lacZ and lacI 
C) lacO and lacI 
D) lacO and lacZ 
E) lacI and lacY

Question 5

For each of the following E. coli partial diploid strains, indicate whether expression of
$\beta$-galactosidase and permease is inducible (I), constitutive (C), or negative (no product made)(N). Assume glucose levels are very low. Which of the strains are able to use lactose as their sole carbon source?

Accepted Answer

@#IMG-DLM& Only strain c is able to use

Question 6

In the lac operon, what acts as the inducer?

Accepted Answer

A) glucose 
B) permease 
C) allolactose 
D) β-galactosidase 
E) transacetylase 
A) glucose 
B) permease 
C) allolactose 
D) β-galactosidase 
E) transacetylase

Question 7

Which molecule functions as the corepressor in the trp operon?

Accepted Answer

The answer of Which molecule functions as the corepressor in...

Question 8

Describe the differences between inducible and repressible operons. How does attenuation differ from inducible or repressible operons?
Which of the two inducible operons you've studied would be active if a cell has the following food sources?
a. only lactose
b. only glucose
c. lactose and glucose

Accepted Answer

Operons like lac and ara that are involv

Question 9

The presence of which combination of molecules would lead to active transcription of an operon?

Accepted Answer

A) activator + corepressor 
B) activator + repressor 
C) inducer + corepressor 
D) repressor + corepressor 
E) activator + inducer 
A) activator + corepressor 
B) activator + repressor 
C) inducer + corepressor 
D) repressor + corepressor 
E) activator + inducer

Question 10

When both glucose and lactose are available in the growth medium, the presence of which molecule is capable of inducing basal transcription of the lac operon?

Accepted Answer

The answer of When both glucose and lactose are available...

Question 11

In the absence of tryptophan, __________.

Accepted Answer

A) the inactive repressor cannot bind trpO, so operon gene transcription occurs 
B) the active repressor binds trpP, so operon gene transcription is repressed 
C) the inducer cannot bind trpO, so operon gene transcription occurs 
D) the active repressor cannot bind trpO, so operon gene transcription is attenuated 
E) the repressor binds the corepressor, and operon gene transcription occurs 
A) the inactive repressor cannot bind trpO, so operon gene transcription occurs 
B) the active repressor binds trpP, so operon gene transcription is repressed 
C) the inducer cannot bind trpO, so operon gene transcription occurs 
D) the active repressor cannot bind trpO, so operon gene transcription is attenuated 
E) the repressor binds the corepressor, and operon gene transcription occurs

Question 12

Which part of the lac operon is cis-dominant?

Accepted Answer

The answer of Which part of the lac operon is...

Question 13

What are the names of the three possible alternative stem loops that can form in mRNA?

Accepted Answer

pause, ant

Question 14

If you wanted to prevent a cell from entering the lysogenic pathway, which gene controlled by PRM would you target for inactivation?

Accepted Answer

A) cro 
B) Q 
C) cI 
D) cII 
E) O 
A) cro 
B) Q 
C) cI 
D) cII 
E) O

Question 15

DNA-binding proteins exert control by binding DNA at specific sequences. Describe how DNA and protein interact at the molecular level. Are proteins able to identify specific DNA sequences, or do they bind to all regions with equal frequency? What motifs are commonly found in DNA-binding proteins?

Accepted Answer

DNA-protein interactions occur when the

Question 16

Explain how transcriptional control by the NrpR protein of the archaeon Methanococcus maripaludis is similar to transcriptional control in bacteria.
It is known that 2-oxoglutarate (2OG)is used by cells as an indicator of nitrogen deficiency. Based on what you know about effector molecules in bacterial operons, how would 2OG behave in
M. maripaludis (as an inducer, a corepressor, etc.)and what effect would this molecule have on NrpR binding?

Accepted Answer

NrpR is a transcriptional repressor prot

Question 17

Which part of the lac operon produces a regulatory protein that is trans-acting?

Accepted Answer

The answer of Which part of the lac operon produces...

Question 18

What protein cleaves the λ repressor monomers to inactivate the repressor protein, and is activated by DNA-damaging agents?

Accepted Answer

The answer of What protein cleaves the λ repressor monomers...

Question 19

What is the role of cis-acting and trans-acting factors in transcription? Explain how these factors play a role in the lac operon, and discuss how complementation can be used to identify where the mutations have occurred (structural genes versus regulatory regions). Which type of mutations
can be complemented by a second gene with normal function? Are IS and OC mutants cis- or
trans-acting?

Accepted Answer

If a factor is trans-acting, genes that

Question 20

In λ phage, which protein, the product of the cI gene, blocks the transcription required to initiate the lytic cycle?

Accepted Answer

A) cro 
B) repressor 
C) enhancer 
D) integrase 
E) operator 
A) cro 
B) repressor 
C) enhancer 
D) integrase 
E) operator

What would be the phenotype of an int⁻ $\lambda$ mutant?

Expression of a(n)________ alters gene transcription in E. coli by activating transcription of specialized heat stress response genes.

Which structural gene of the lac operon can be mutated without affecting the cell's ability to break down lactose?

Which of the following can be mutated to result in constitutive expression from the lac operon?

In the lac operon, what acts as the inducer?

Which molecule functions as the corepressor in the trp operon?

Describe the differences between inducible and repressible operons. How does attenuation differ from inducible or repressible operons? Which of the two inducible operons you've studied would be active if a cell has the following food sources? a. only lactose b. only glucose c. lactose and glucose

The presence of which combination of molecules would lead to active transcription of an operon?

When both glucose and lactose are available in the growth medium, the presence of which molecule is capable of inducing basal transcription of the lac operon?

In the absence of tryptophan, __________.

Which part of the lac operon is cis-dominant?

What are the names of the three possible alternative stem loops that can form in mRNA?

If you wanted to prevent a cell from entering the lysogenic pathway, which gene controlled by P_RM would you target for inactivation?

DNA-binding proteins exert control by binding DNA at specific sequences. Describe how DNA and protein interact at the molecular level. Are proteins able to identify specific DNA sequences, or do they bind to all regions with equal frequency? What motifs are commonly found in DNA-binding proteins?

Which part of the lac operon produces a regulatory protein that is trans-acting?

What protein cleaves the λ repressor monomers to inactivate the repressor protein, and is activated by DNA-damaging agents?

In λ phage, which protein, the product of the cI gene, blocks the transcription required to initiate the lytic cycle?

The Molecular Basis of Heredity, Variation, and Evolution

Transmission Genetics

Cell Division and Chromosome Heredity

Gene Interaction

Genetic Linkage and Mapping in Eukaryotes

Genetic Analysis and Mapping in Bacteria and Bacteriophages

Dna Structure and Replication

Molecular Biology and Transcription and Rna Processing

The Molecular Biology of Translation

The Integration of Genetic Approaches: Understanding Sickle Cell Disease

Chromosome Structure

Gene Mutation, Dna Repair, and Homologous Recombination

Chromosome Aberrations and Transposition

Regulation of Gene Expression in Eukaryotes

Forward Genetics and Recombinant Dna Technology

Applications of Recombinant Dna Technology and Reverse Genetics

Genomics: Genetics From a Whole-Genome Perspective

Cytoplasmic Inheritance and the Evolution of Organelle Genomes

Developmental Genetics

Genetic Analysis of Quantitative Traits

Population Genetics and Evolution

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Exam 14: Regulation of Gene Expression in Bacteria and Bacteriophages

What would be the phenotype of an int− λ\lambdaλ mutant?

Expression of a(n)________ alters gene transcription in E. coli by activating transcription of specialized heat stress response genes.

Which structural gene of the lac operon can be mutated without affecting the cell's ability to break down lactose?

Which of the following can be mutated to result in constitutive expression from the lac operon?

In the lac operon, what acts as the inducer?

Which molecule functions as the corepressor in the trp operon?

Describe the differences between inducible and repressible operons. How does attenuation differ from inducible or repressible operons? Which of the two inducible operons you've studied would be active if a cell has the following food sources? a. only lactose b. only glucose c. lactose and glucose

The presence of which combination of molecules would lead to active transcription of an operon?

When both glucose and lactose are available in the growth medium, the presence of which molecule is capable of inducing basal transcription of the lac operon?

In the absence of tryptophan, __________.

Which part of the lac operon is cis-dominant?

What are the names of the three possible alternative stem loops that can form in mRNA?

If you wanted to prevent a cell from entering the lysogenic pathway, which gene controlled by PRM would you target for inactivation?

DNA-binding proteins exert control by binding DNA at specific sequences. Describe how DNA and protein interact at the molecular level. Are proteins able to identify specific DNA sequences, or do they bind to all regions with equal frequency? What motifs are commonly found in DNA-binding proteins?

Which part of the lac operon produces a regulatory protein that is trans-acting?

What protein cleaves the λ repressor monomers to inactivate the repressor protein, and is activated by DNA-damaging agents?

In λ phage, which protein, the product of the cI gene, blocks the transcription required to initiate the lytic cycle?

The Molecular Basis of Heredity, Variation, and Evolution

Transmission Genetics

Cell Division and Chromosome Heredity

Gene Interaction

Genetic Linkage and Mapping in Eukaryotes

Genetic Analysis and Mapping in Bacteria and Bacteriophages

Dna Structure and Replication

Molecular Biology and Transcription and Rna Processing

The Molecular Biology of Translation

The Integration of Genetic Approaches: Understanding Sickle Cell Disease

Chromosome Structure

Gene Mutation, Dna Repair, and Homologous Recombination

Chromosome Aberrations and Transposition

Regulation of Gene Expression in Eukaryotes

Forward Genetics and Recombinant Dna Technology

Applications of Recombinant Dna Technology and Reverse Genetics

Genomics: Genetics From a Whole-Genome Perspective

Cytoplasmic Inheritance and the Evolution of Organelle Genomes

Developmental Genetics

Genetic Analysis of Quantitative Traits

Population Genetics and Evolution

Filters

What would be the phenotype of an int⁻ $\lambda$ mutant?

If you wanted to prevent a cell from entering the lysogenic pathway, which gene controlled by P_RM would you target for inactivation?