Question 1

Describe what happens to the lac operon in the presence of both lactose and glucose.

Accepted Answer

In the presence of both lactose and gluc

Question 2

The little amount of sigma H that is made at 30°C is ________ by the DnaK/GrpE/DnaJ chaperones.

Accepted Answer

A)  enhanced 
B)  activated 
C)  degraded 
D)  protected 
E)  folded 
A)  enhanced 
B)  activated 
C)  degraded 
D)  protected 
E)  folded

Question 3

A feature common to all control mechanisms is

Accepted Answer

A)  quorum sensing. 
B)  phosphorylation cascades. 
C)  the ability to sense that something inside or around the cell has changed. 
D)  housekeeping enzymes. 
E)  increased or decreased gene expression. 
A)  quorum sensing. 
B)  phosphorylation cascades. 
C)  the ability to sense that something inside or around the cell has changed. 
D)  housekeeping enzymes. 
E)  increased or decreased gene expression.

Question 4

Integrated circuits are involved in all of the following EXCEPT

Accepted Answer

A)  controlling chemotactic activities of a cell. 
B)  coupling the genetic and biochemical control of a metabolic pathway. 
C)  timing the events of a developmental cycle. 
D)  having an influence on nitrogen metabolism. 
E)  specifically inverting the flagellin genes. 
A)  controlling chemotactic activities of a cell. 
B)  coupling the genetic and biochemical control of a metabolic pathway. 
C)  timing the events of a developmental cycle. 
D)  having an influence on nitrogen metabolism. 
E)  specifically inverting the flagellin genes.

Question 5

The role of the Hin recombinase is to

Accepted Answer

A)  recombine specific segments of the DNA of Haemophilus influenzae. 
B)  recombine specific segments of flagellin genes in Neisseria gonorrhoeae. 
C)  recombine specific segments of MCP genes in Salmonella enterica. 
D)  recombine specific segments of flagellin genes in Salmonella enterica. 
E)  repair damage in DNA. 
A)  recombine specific segments of the DNA of Haemophilus influenzae. 
B)  recombine specific segments of flagellin genes in Neisseria gonorrhoeae. 
C)  recombine specific segments of MCP genes in Salmonella enterica. 
D)  recombine specific segments of flagellin genes in Salmonella enterica. 
E)  repair damage in DNA.

Question 6

The stringent response relies on the production of

Accepted Answer

A)  pG. 
B)  ppG. 
C)  pppG. 
D)  pGp. 
E)  ppGpp. 
A)  pG. 
B)  ppG. 
C)  pppG. 
D)  pGp. 
E)  ppGpp.

Question 7

Which of the following statements is true concerning the use of cyclic di-GMP as a second messenger?

Accepted Answer

A)  It activates the expression of flagellin genes and thus enhances motility. 
B)  It is found in all microbes: bacteria, archaea, and eukaryotic microbes. 
C)  The action of diguanylate cyclase produces it. 
D)  It decreases in level as biofilm is produced. 
E)  Phosphodiesterase can convert GMP to cyclic di-GMP. 
A)  It activates the expression of flagellin genes and thus enhances motility. 
B)  It is found in all microbes: bacteria, archaea, and eukaryotic microbes. 
C)  The action of diguanylate cyclase produces it. 
D)  It decreases in level as biofilm is produced. 
E)  Phosphodiesterase can convert GMP to cyclic di-GMP.

Question 8

Phase variation in Salmonella enterica involves

Accepted Answer

A)  gene inversion. 
B)  chemotaxis. 
C)  outer membrane proteins. 
D)  sRNA. 
E)  slipped-strand mispairing. 
A)  gene inversion. 
B)  chemotaxis. 
C)  outer membrane proteins. 
D)  sRNA. 
E)  slipped-strand mispairing.

Question 9

Glucose transport into the cell brings about a phenomenon known as inducer exclusion.
Describe how this functions with respect to the lac operon.

Accepted Answer

In the presence of glucose, the PTS syst

Question 10

The regulatory activity of sRNA

Accepted Answer

A)  codes for a sigma factor. 
B)  prevents CRP interaction with RNA polymerase, thereby blocking its access to the promoter. 
C)  synthesizes ppGpp. 
D)  targets mRNAs for degradation. 
E)  creates an attenuator stem loop. 
A)  codes for a sigma factor. 
B)  prevents CRP interaction with RNA polymerase, thereby blocking its access to the promoter. 
C)  synthesizes ppGpp. 
D)  targets mRNAs for degradation. 
E)  creates an attenuator stem loop.

Question 11

The stringent response involves all EXCEPT

Accepted Answer

A)  downregulation of rRNA synthesis. 
B)  downregulation of tRNA synthesis. 
C)  ATP. 
D)  GTP. 
E)  a lack of change in gene expression. 
A)  downregulation of rRNA synthesis. 
B)  downregulation of tRNA synthesis. 
C)  ATP. 
D)  GTP. 
E)  a lack of change in gene expression.

Question 12

Which of the following is a second messenger that helps to regulate biofilm production?

Accepted Answer

A)  ppGpp 
B)  ATP 
C)  cAMP 
D)  cGMP 
E)  cdiGMP 
A)  ppGpp 
B)  ATP 
C)  cAMP 
D)  cGMP 
E)  cdiGMP

Question 13

________ prevent transcription, whereas ________ stimulate transcription.

Accepted Answer

A)  Activators; repressors 
B)  Inducers; corepressors 
C)  Corepressors; inducers 
D)  Regulators; repressors 
E)  Repressors; activators 
A)  Activators; repressors 
B)  Inducers; corepressors 
C)  Corepressors; inducers 
D)  Regulators; repressors 
E)  Repressors; activators

Question 14

The value of studying a transcriptome rather than a genome is that

Accepted Answer

A)  RNA is much easier to work with than DNA. 
B)  using bacterial RNA eliminates the introns they all have. 
C)  one can get a snapshot of what genes are expressed under some conditions but not others. 
D)  a transcriptome is more related to the protein. 
E)  deep sequencing can only be performed on RNA. 
A)  RNA is much easier to work with than DNA. 
B)  using bacterial RNA eliminates the introns they all have. 
C)  one can get a snapshot of what genes are expressed under some conditions but not others. 
D)  a transcriptome is more related to the protein. 
E)  deep sequencing can only be performed on RNA.

Question 15

The best description of the initial step in the regulatory process shown below is

Accepted Answer

A)  an sRNA is produced that can then be used to turn on genes. 
B)  an sRNA is produced that can then be used to turn off genes. 
C)  a sigma factor mRNA is transcribed and forms secondary structures at lower temperatures. When heated, the structures melt and the mRNA for the heat shock sigma factor, rpoH, can be translated. 
D)  The hairpins contain codons for a needed amino acid. When amino acid is lacking, the ribosome stalls and prevents its formation, thus allowing translation. 
E)  The hairpins contain codons for needed amino acids. When amino acid is present, the ribosome stalls and prevents the formation of hairpins, thus allowing translation. 
A)  an sRNA is produced that can then be used to turn on genes. 
B)  an sRNA is produced that can then be used to turn off genes. 
C)  a sigma factor mRNA is transcribed and forms secondary structures at lower temperatures. When heated, the structures melt and the mRNA for the heat shock sigma factor, rpoH, can be translated. 
D)  The hairpins contain codons for a needed amino acid. When amino acid is lacking, the ribosome stalls and prevents its formation, thus allowing translation. 
E)  The hairpins contain codons for needed amino acids. When amino acid is present, the ribosome stalls and prevents the formation of hairpins, thus allowing translation.

Question 16

A quorum-sensing gene system requires the accumulation of a secreted small molecule called a(n)

Accepted Answer

A)  autoinducer. 
B)  activator. 
C)  repressor. 
D)  inducer. 
E)  corepressor. 
A)  autoinducer. 
B)  activator. 
C)  repressor. 
D)  inducer. 
E)  corepressor.

Question 17

Which of the following statements about riboswitches is true?

Accepted Answer

A)  They are found mainly at the 3' end of a mRNA. 
B)  They are capable of binding to a ligand and activating transcription but do not repress transcription. 
C)  They can control transcription but no translation. 
D)  Ligands that can bind range from vitamins, amino acids, magnesium, and fluoride. 
E)  They have no secondary structures involved in their control. 
A)  They are found mainly at the 3' end of a mRNA. 
B)  They are capable of binding to a ligand and activating transcription but do not repress transcription. 
C)  They can control transcription but no translation. 
D)  Ligands that can bind range from vitamins, amino acids, magnesium, and fluoride. 
E)  They have no secondary structures involved in their control.

Question 18

In the regulation of chemotaxis, proteins are modified in which of the following ways?

Accepted Answer

A)  phosphorylations 
B)  methylation 
C)  feedback inhibition 
D)  phosphorylation and methylation 
E)  feedback inhibition, phosphorylation, and methylation 
A)  phosphorylations 
B)  methylation 
C)  feedback inhibition 
D)  phosphorylation and methylation 
E)  feedback inhibition, phosphorylation, and methylation

Question 19

How does the AraC regulatory protein turn on transcription in the presence of arabinose?

Accepted Answer

A)  With the addition of arabinose, AraC no longer dimerizes and will form a large loop by binding to araO and aria, and thus can interact with RNA polymerase to permit transcription. 
B)  The dimer will form a large loop by binding to araO and aria, and thus can interact with RNA polymerase to permit transcription. 
C)  With the addition, AraC no longer dimerizes and thus can interact with RNA polymerase to permit transcription. 
D)  It becomes less flexible, so that a monomer can bind to araI1 and araI2 and interact with RNA polymerase to permit transcription. 
E)  It becomes more flexible, so that the dimer can bind to araI1 and araI2 and interact with RNA polymerase to permit transcription. 
A)  With the addition of arabinose, AraC no longer dimerizes and will form a large loop by binding to araO and aria, and thus can interact with RNA polymerase to permit transcription. 
B)  The dimer will form a large loop by binding to araO and aria, and thus can interact with RNA polymerase to permit transcription. 
C)  With the addition, AraC no longer dimerizes and thus can interact with RNA polymerase to permit transcription. 
D)  It becomes less flexible, so that a monomer can bind to araI1 and araI2 and interact with RNA polymerase to permit transcription. 
E)  It becomes more flexible, so that the dimer can bind to araI1 and araI2 and interact with RNA polymerase to permit transcription.

Question 20

Which of the following is NOT true of sRNA genes?

Accepted Answer

A)  They have a ribosomal-binding site. 
B)  They occur between genes. 
C)  They share homology between related species. 
D)  They can act as antisense RNAs. 
E)  They play a role in regulating genes involved in oxidative stress, acid resistance, and quorum sensing. 
A)  They have a ribosomal-binding site. 
B)  They occur between genes. 
C)  They share homology between related species. 
D)  They can act as antisense RNAs. 
E)  They play a role in regulating genes involved in oxidative stress, acid resistance, and quorum sensing.

Exam 10: Molecular Regulation

Describe what happens to the lac operon in the presence of both lactose and glucose.

The little amount of sigma H that is made at 30°C is ________ by the DnaK/GrpE/DnaJ chaperones.

A feature common to all control mechanisms is

Integrated circuits are involved in all of the following EXCEPT

The role of the Hin recombinase is to

The stringent response relies on the production of

Which of the following statements is true concerning the use of cyclic di-GMP as a second messenger?

Phase variation in Salmonella enterica involves

Glucose transport into the cell brings about a phenomenon known as inducer exclusion. Describe how this functions with respect to the lac operon.

The regulatory activity of sRNA

The stringent response involves all EXCEPT

Which of the following is a second messenger that helps to regulate biofilm production?

________ prevent transcription, whereas ________ stimulate transcription.

The value of studying a transcriptome rather than a genome is that

The best description of the initial step in the regulatory process shown below is

A quorum-sensing gene system requires the accumulation of a secreted small molecule called a(n)

Which of the following statements about riboswitches is true?

In the regulation of chemotaxis, proteins are modified in which of the following ways?

How does the AraC regulatory protein turn on transcription in the presence of arabinose?

Which of the following is NOT true of sRNA genes?

Microbial Life: Origin and Discovery

Observing the Microbial Cell

Cell Structure and Function

Bacterial Culture, Growth, and Development

Environmental Influences and Control of Microbial Growth

Viruses

Genomes and Chromosomes

Transcription, Translation, and Bioinformatics

Gene Transfer, Mutations, and Genome Evolution

Viral Molecular Biology

Biotechniques and Synthetic Biology

Energetics and Catabolism

Electron Flow in Organotrophy, Lithotrophy, and Phototrophy

Biosynthesis

Food and Industrial Microbiology

Origins and Evolution

Bacterial Diversity

Archaeal Diversity

Eukaryotic Diversity

Microbial Ecology

Microbes in Global Elemental Cycles

Human Microbiota and Innate Immunity

The Adaptive Immune Response

Microbial Pathogenesis

Microbial Diseases

Antimicrobial Therapy

Clinical Microbiology and Epidemiology

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prevent transcription, whereas stimulate transcription.