Question 1

A bacterium is unable to transport lactose into the cell to be broken down. Which gene is likely mutated in this bacterium?

Accepted Answer

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

Question 2

The presence of which combination of molecules could prevent transcription of a repressible operon?

Accepted Answer

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

Question 3

Which of the following would NOT occur in a phage undergoing induction?

Accepted Answer

A)  The transcription level of the int gene will increase, leading to production of the integrase. 
B)  Cleavage of the h repressor monomers inactivates the repressor protein. 
C)  There will be activation of the protease activity of RecA. 
D)  The transcription level of the xis gene will increase, leading to production of the enzyme excisionase. 
E)  UV damage to DNA can trigger the switch from lysogeny to the lytic cycle. 
A)  The transcription level of the int gene will increase, leading to production of the integrase. 
B)  Cleavage of the h repressor monomers inactivates the repressor protein. 
C)  There will be activation of the protease activity of RecA. 
D)  The transcription level of the xis gene will increase, leading to production of the enzyme excisionase. 
E)  UV damage to DNA can trigger the switch from lysogeny to the lytic cycle. A

Question 4

The electrophoresis gel shown below is from a DNase I footprint analysis of an operon transcription control region. Separate samples of control- region DNA were exposed to DNase I and run in the following lanes: uprotected DNA is in lane 1, DNA protected by repressor is in lane 2, and DNA protected by RNA polymerase is in lane 3.   Based on the gel, what nucleotide positions are occupied by the repressor and RNA polymerase?

Accepted Answer

A)  19 through 29 by the repressor and 7 through 24 RNA polymerase 
B)  1 through 18 by the repressor and 1 through 6 by RNA polymerase 
C)  30 through 35 by the repressor and 7 through 24 by RNA polymerase 
D)  1 through 18 by the repressor and 25 through 35 by RNA polymerase 
E)  19 through 29 by the repressor and 1 through 6 by RNA polymerase 
A)  19 through 29 by the repressor and 7 through 24 RNA polymerase 
B)  1 through 18 by the repressor and 1 through 6 by RNA polymerase 
C)  30 through 35 by the repressor and 7 through 24 by RNA polymerase 
D)  1 through 18 by the repressor and 25 through 35 by RNA polymerase 
E)  19 through 29 by the repressor and 1 through 6 by RNA polymerase

Question 5

Which region of the lac operon would you target if you want to disrupt the - 10 and - 35 consensus sequences?

Accepted Answer

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

Question 6

Which of the following regarding riboswitches is correct?

Accepted Answer

A)  They can use repressors to bind to DNA sequences called operators. 
B)  Low concentrations of a small regulatory molecule can cause cleavage of the mRNA. 
C)  The binding of small regulatory molecules can generate Shine- Dalgarno sequester stem loops that lead to increased translation. 
D)  The binding of small regulatory molecules can generate termination stem loops that lead to increased transcription. 
E)  They can regulate bacterial transcription, translation, and mRNA stability. 
A)  They can use repressors to bind to DNA sequences called operators. 
B)  Low concentrations of a small regulatory molecule can cause cleavage of the mRNA. 
C)  The binding of small regulatory molecules can generate Shine- Dalgarno sequester stem loops that lead to increased translation. 
D)  The binding of small regulatory molecules can generate termination stem loops that lead to increased transcription. 
E)  They can regulate bacterial transcription, translation, and mRNA stability.

Question 7

Which part of the lac operon is cis- dominant?

Accepted Answer

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

Question 8

If a corepressor is inhibited, what effect would you expect to see on transcription in a repressible operon?

Accepted Answer

Transcript

Question 9

Using the autoradiograph of a DNA sequencing gel below determine which of the following is the sequence of the 35- bp operon transcription control region.

Accepted Answer

The DNA sequence is determined

Question 10

What are the two active sites or "domains" on a repressor protein?

Accepted Answer

DNA- bindi

Question 11

Bacteria grown at 45°C initiate expression of which two types of proteins?

Accepted Answer

heat shock

Question 12

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 13

What is the process by which a bacterium switches from a lysogenic to lytic cycle?

Accepted Answer

The answer of What is the process by which a...

Question 14

Which of the following mutations of the trpL region would be least likely to affect attenuation of trp operon transcription?

Accepted Answer

A)  an insertion of two nucleotides immediately after the polypeptide stop codon 
B)  an insertion of two nucleotides immediately following the polypeptide start codon 
C)  a deletion of the uracil nucleotides immediately following region 4 
D)  a deletion of region 4 
E)  a deletion of the start (AUG) codon of the trpL polypeptide 
A)  an insertion of two nucleotides immediately after the polypeptide stop codon 
B)  an insertion of two nucleotides immediately following the polypeptide start codon 
C)  a deletion of the uracil nucleotides immediately following region 4 
D)  a deletion of region 4 
E)  a deletion of the start (AUG) codon of the trpL polypeptide

Question 15

What would be the phenotype of an int- h mutant?

Accepted Answer

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

Question 16

Most of the regulation of gene expression in bacteria occurs at the___________ level.

Accepted Answer

The answer of Most of the regulation of gene expression...

Question 17

You want to design a repressor protein mutant. Which protein domain is the best target for preventing binding of the corepressor?

Accepted Answer

A)  activator binding site 
B)  allosteric domain 
C)  DNA- binding domain 
D)  helix- turn- helix domain 
E)  promoter domain 
A)  activator binding site 
B)  allosteric domain 
C)  DNA- binding domain 
D)  helix- turn- helix domain 
E)  promoter domain

Question 18

What is the purpose of the lac operon, and under what circumstances is it activated? Describe the structure of the lac operon, including the repressor protein, structural genes, and regulatory regions of the operon. What is the role of catabolite repression in the lac operon?

Accepted Answer

binding. LacO, which binds the repressor

Question 19

In h phage, a mutation that inactivates which of the following genes should leave the mutated phage strain capable of establishing lysogeny?

Accepted Answer

A)  cro 
B)  N 
C)  int 
D)  cI 
E)  cII 
A)  cro 
B)  N 
C)  int 
D)  cI 
E)  cII

Question 20

Catabolite repression refers to the repression of the lac operon in the presence of which catabolite?

Accepted Answer

The answer of Catabolite repression refers to the repression of...

A bacterium is unable to transport lactose into the cell to be broken down. Which gene is likely mutated in this bacterium?

The presence of which combination of molecules could prevent transcription of a repressible operon?

Which of the following would NOT occur in a phage undergoing induction?

Which region of the lac operon would you target if you want to disrupt the - 10 and - 35 consensus sequences?

Which of the following regarding riboswitches is correct?

Which part of the lac operon is cis- dominant?

If a corepressor is inhibited, what effect would you expect to see on transcription in a repressible operon?

Using the autoradiograph of a DNA sequencing gel below determine which of the following is the sequence of the 35- bp operon transcription control region.

What are the two active sites or "domains" on a repressor protein?

Bacteria grown at 45°C initiate expression of which two types of proteins?

What is the process by which a bacterium switches from a lysogenic to lytic cycle?

Which of the following mutations of the trpL region would be least likely to affect attenuation of trp operon transcription?

What would be the phenotype of an int- h mutant?

Most of the regulation of gene expression in bacteria occurs at the___________ level.

You want to design a repressor protein mutant. Which protein domain is the best target for preventing binding of the corepressor?

What is the purpose of the lac operon, and under what circumstances is it activated? Describe the structure of the lac operon, including the repressor protein, structural genes, and regulatory regions of the operon. What is the role of catabolite repression in the lac operon?

In h phage, a mutation that inactivates which of the following genes should leave the mutated phage strain capable of establishing lysogeny?

Catabolite repression refers to the repression of the lac operon in the presence of which catabolite?

The Molecular Basis of Heredity, Variation, and Evolution

Transmission Genetics

Cell Division and Chromosome Heredity

Inheritance Patterns of Single Genes and Gene Interaction

Genetic Linkage and Mapping in Eukaryotes

Genetic Analysis and Mapping in Bacteria and Bacteriophage

Dna Structure and Replication

Molecular Biology of Transcription and Rna Processing

The Molecular Biology of Translation

Chromosome Chapter Title Tbd

Gene Mutation, Dna Repair, and Homologous Recombination

Regulation of Gene Expression in Bacteria and Bacteriophage

Regulation of Gene Expression in Eukaryotes

Analysis of Gene Function by Forward Genetics and Reverse Genetics

Recombinant Dna Technology and Its Applications

Genomics: Genetics From a Whole-Genome Perspective

Organelle Inheritance and the Evolution of Organelle Genomes

Developmental Genetics

Genetic Analysis of Quantitative Traits

Population Genetics and Evolution at the Population, Species, and Molecular Levels

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Exam 12: Chromosome Exam Title Tbd

A bacterium is unable to transport lactose into the cell to be broken down. Which gene is likely mutated in this bacterium?

The presence of which combination of molecules could prevent transcription of a repressible operon?

Which of the following would NOT occur in a phage undergoing induction?

Which region of the lac operon would you target if you want to disrupt the - 10 and - 35 consensus sequences?

Which of the following regarding riboswitches is correct?

Which part of the lac operon is cis- dominant?

If a corepressor is inhibited, what effect would you expect to see on transcription in a repressible operon?

Using the autoradiograph of a DNA sequencing gel below determine which of the following is the sequence of the 35- bp operon transcription control region.

What are the two active sites or "domains" on a repressor protein?

Bacteria grown at 45°C initiate expression of which two types of proteins?

What is the process by which a bacterium switches from a lysogenic to lytic cycle?

Which of the following mutations of the trpL region would be least likely to affect attenuation of trp operon transcription?

What would be the phenotype of an int- h mutant?

Most of the regulation of gene expression in bacteria occurs at the___________ level.

You want to design a repressor protein mutant. Which protein domain is the best target for preventing binding of the corepressor?

What is the purpose of the lac operon, and under what circumstances is it activated? Describe the structure of the lac operon, including the repressor protein, structural genes, and regulatory regions of the operon. What is the role of catabolite repression in the lac operon?

In h phage, a mutation that inactivates which of the following genes should leave the mutated phage strain capable of establishing lysogeny?

Catabolite repression refers to the repression of the lac operon in the presence of which catabolite?

The Molecular Basis of Heredity, Variation, and Evolution

Transmission Genetics

Cell Division and Chromosome Heredity

Inheritance Patterns of Single Genes and Gene Interaction

Genetic Linkage and Mapping in Eukaryotes

Genetic Analysis and Mapping in Bacteria and Bacteriophage

Dna Structure and Replication

Molecular Biology of Transcription and Rna Processing

The Molecular Biology of Translation

Chromosome Chapter Title Tbd

Gene Mutation, Dna Repair, and Homologous Recombination

Regulation of Gene Expression in Bacteria and Bacteriophage

Regulation of Gene Expression in Eukaryotes

Analysis of Gene Function by Forward Genetics and Reverse Genetics

Recombinant Dna Technology and Its Applications

Genomics: Genetics From a Whole-Genome Perspective

Organelle Inheritance and the Evolution of Organelle Genomes

Developmental Genetics

Genetic Analysis of Quantitative Traits

Population Genetics and Evolution at the Population, Species, and Molecular Levels

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