Question 1

Why is it advantageous for transcription factors to be multimeric and for their binding sites to be clustered?

Accepted Answer

A) The strength of the DNA-protein interactions is increased. 
B) The DNA sequence specificity of each DNA-protein interaction is increased. 
C) Each DNA-protein complex is better able to bind to RNA polymerase. 
D) Competition for binding between different transcription factors for the same regulatory region is decreased. 
A) The strength of the DNA-protein interactions is increased. 
B) The DNA sequence specificity of each DNA-protein interaction is increased. 
C) Each DNA-protein complex is better able to bind to RNA polymerase. 
D) Competition for binding between different transcription factors for the same regulatory region is decreased.

Question 2

How do negative regulators such as the Lac repressor prevent RNA polymerase from initiating transcription?

Accepted Answer

A) by blocking the ribosome binding site 
B) by forming a loop in the operator that restricts the passage of the polymerase 
C) by physically blocking the DNA binding site of RNA polymerase 
D) by binding to the polymerase to inhibit its catalytic activity 
A) by blocking the ribosome binding site 
B) by forming a loop in the operator that restricts the passage of the polymerase 
C) by physically blocking the DNA binding site of RNA polymerase 
D) by binding to the polymerase to inhibit its catalytic activity

Question 3

How is glucose involved in catabolite repression of the lac operon?

Accepted Answer

A) Glucose causes cAMP levels to increase, which leads to increased CRP binding and the lac operon is activated even when lactose is present. 
B) Glucose causes cAMP levels to decrease, which leads to decreased CRP binding and the lac operon is repressed even when lactose is present. 
C) Glucose is also a substrate for β-galactosidase and thus competes with lactose for this enzyme. 
D) Glucose activates transcription of the lacI gene to increase the amount of Lac repressor in the cell. 
A) Glucose causes cAMP levels to increase, which leads to increased CRP binding and the lac operon is activated even when lactose is present. 
B) Glucose causes cAMP levels to decrease, which leads to decreased CRP binding and the lac operon is repressed even when lactose is present. 
C) Glucose is also a substrate for β-galactosidase and thus competes with lactose for this enzyme. 
D) Glucose activates transcription of the lacI gene to increase the amount of Lac repressor in the cell.

Question 4

Catabolic pathways that break down complex substances into more usable units are usually regulated in response to the

Accepted Answer

A) end products of the pathway. 
B) levels of the molecule that is to be broken down. 
C) other metabolites that are limiting. 
D) levels of enzymes in the pathway. 
A) end products of the pathway. 
B) levels of the molecule that is to be broken down. 
C) other metabolites that are limiting. 
D) levels of enzymes in the pathway.

Question 5

In the regulation of the trp operon, tryptophan acts as a(n)

Accepted Answer

A) repressor. 
B) attenuator. 
C) activator. 
D) effector. 
E) operator. 
A) repressor. 
B) attenuator. 
C) activator. 
D) effector. 
E) operator.

Question 6

What term describes regulation of the trp operon that can occur even in trpR− mutants, thus suggesting that the mechanism is repressor-independent?

Accepted Answer

A) modulation 
B) derepression 
C) attenuation 
D) amplification 
A) modulation 
B) derepression 
C) attenuation 
D) amplification

Question 7

A crucial step in the regulation of most bacterial genes occurs

Accepted Answer

A) at transcription initiation. 
B) during RNA splicing. 
C) during nuclear export of mRNA. 
D) when nonsense suppressors translate mRNAs. 
A) at transcription initiation. 
B) during RNA splicing. 
C) during nuclear export of mRNA. 
D) when nonsense suppressors translate mRNAs.

Question 8

The transition from transcriptional initiation to elongation involves

Accepted Answer

A) binding of sigma factor. 
B) release of sigma factor. 
C) release of RNA polymerase from DNA. 
D) binding of RNA polymerase to DNA. 
E) binding of rho factor. 
A) binding of sigma factor. 
B) release of sigma factor. 
C) release of RNA polymerase from DNA. 
D) binding of RNA polymerase to DNA. 
E) binding of rho factor.

Question 9

Anabolic pathways involved in the synthesis of essential molecules are usually regulated in response to

Accepted Answer

A) the end product of the pathway. 
B) a substrate of the pathway. 
C) other metabolites that are limiting. 
D) the levels of enzymes in the pathway. 
A) the end product of the pathway. 
B) a substrate of the pathway. 
C) other metabolites that are limiting. 
D) the levels of enzymes in the pathway.

Question 10

Proteins whose conformations change when they are bound to an effector molecule are called

Accepted Answer

A) enzymes. 
B) allosteric proteins. 
C) regulatory proteins. 
D) activator proteins. 
E) inhibitory proteins. 
A) enzymes. 
B) allosteric proteins. 
C) regulatory proteins. 
D) activator proteins. 
E) inhibitory proteins.

Question 11

Initiation of transcription by RNA polymerase involves the binding of which of the following subunits to the core enzyme?

Accepted Answer

A) delta 
B) sigma 
C) gamma 
D) alpha 
E) zeta 
A) delta 
B) sigma 
C) gamma 
D) alpha 
E) zeta

Question 12

You have identified a 50 nucleotide deletion that is not within an open reading frame in an otherwise wild-type prokaryotic genome.You identify five mRNAs that are not translated in these mutant bacteria; the five mRNAs are transcribed from five different genes located far from the deletion.Select the most likely explanation for the effect of this deletion.

Accepted Answer

A) The deletion is within an antisense RNA that regulates translation of all five genes. 
B) The deletion prevents expression of a small RNA that regulates translation of all five genes. 
C) The deletion removes an aptamer in an RNA leader sequence. 
D) The deletion removes an effector molecule that regulates transcription. 
A) The deletion is within an antisense RNA that regulates translation of all five genes. 
B) The deletion prevents expression of a small RNA that regulates translation of all five genes. 
C) The deletion removes an aptamer in an RNA leader sequence. 
D) The deletion removes an effector molecule that regulates transcription.

Question 13

Fifteen different strains of bacteria are auxotrophic for maltose and their mutations do not complement each other.The mutations in these bacteria map to the same DNA region using transformation of random fragments of genomic DNA.Only two different enzymes participate in the maltose biosynthetic pathway, and the genes for both are within a single operon.What does this data suggest?

Accepted Answer

A) There are fifteen enzymes in maltose metabolism. 
B) All the strains have mutations that prevent transcription of the operon. 
C) Fifteen genes encode maltose biosynthesis enzymes, but only two genes are crucial. 
D) Maltose is the preferred sugar source for the mutant bacteria. 
A) There are fifteen enzymes in maltose metabolism. 
B) All the strains have mutations that prevent transcription of the operon. 
C) Fifteen genes encode maltose biosynthesis enzymes, but only two genes are crucial. 
D) Maltose is the preferred sugar source for the mutant bacteria.

Question 14

Transcription and translation can be coupled in bacteria but not eukaryotes because

Accepted Answer

A) no nuclear membrane exists in prokaryotes. 
B) no nuclear membrane exists in eukaryotes. 
C) the bacterial DNA is in a single chromosome. 
D) eukaryotic chromosomes are found in nucleoids. 
A) no nuclear membrane exists in prokaryotes. 
B) no nuclear membrane exists in eukaryotes. 
C) the bacterial DNA is in a single chromosome. 
D) eukaryotic chromosomes are found in nucleoids.

Question 15

V.fischeri senses the density of V.fischeri cells in the environment by

Accepted Answer

A) secretion of a molecule that can then be internalized and bound to a receptor in the cytoplasm. 
B) cell surface receptors that interact with other cell surface receptors on nearby cells. 
C) a cell surface receptor that binds to a molecule secreted by cells in the environment. 
D) a cytoplasmic receptor that binds to the LuxC protein. 
A) secretion of a molecule that can then be internalized and bound to a receptor in the cytoplasm. 
B) cell surface receptors that interact with other cell surface receptors on nearby cells. 
C) a cell surface receptor that binds to a molecule secreted by cells in the environment. 
D) a cytoplasmic receptor that binds to the LuxC protein.

Question 16

Why is the analysis of transcriptomes useful for genetics research?

Accepted Answer

A) It can reveal many aspects of gene regulation. 
B) It is easy to do without computer programs. 
C) It can help discover nontranscribed DNA regions. 
D) It directly identifies transcription factor binding sites. 
A) It can reveal many aspects of gene regulation. 
B) It is easy to do without computer programs. 
C) It can help discover nontranscribed DNA regions. 
D) It directly identifies transcription factor binding sites.

Question 17

When RNA-Seq is performed before and after heat shock of bacterial cells, computer analysis would be expected to show

Accepted Answer

A) very few changes in the cDNAs sequenced because the response to heat shock occurs primarily at the protein level. 
B) after heat shock, an increase in the average length of sequence reads of cDNAs that encode molecular chaperone proteins. 
C) after heat shock, an increase in the number of sequence reads of cDNAs that encode molecular chaperone proteins. 
D) after heat shock, a decrease in the number of sequence reads of cDNAs that encode molecular chaperone proteins. 
A) very few changes in the cDNAs sequenced because the response to heat shock occurs primarily at the protein level. 
B) after heat shock, an increase in the average length of sequence reads of cDNAs that encode molecular chaperone proteins. 
C) after heat shock, an increase in the number of sequence reads of cDNAs that encode molecular chaperone proteins. 
D) after heat shock, a decrease in the number of sequence reads of cDNAs that encode molecular chaperone proteins.

Question 18

How does a positive regulator affect transcription by RNA polymerase in prokaryotes?

Accepted Answer

A) by allowing passage of the polymerase through an operator 
B) by interacting with RNA polymerase to increase the frequency of transcription initiation 
C) by causing the helix to unwind in the operator allowing easier initiation 
D) by making the transcription start site more exposed to the polymerase 
A) by allowing passage of the polymerase through an operator 
B) by interacting with RNA polymerase to increase the frequency of transcription initiation 
C) by causing the helix to unwind in the operator allowing easier initiation 
D) by making the transcription start site more exposed to the polymerase

Question 19

In the trp operon, attenuation occurs through translation of two Trp codons in the leader sequence.What would happen if these two codons were mutated to stop codons?

Accepted Answer

A) Region 1 will bind to region 3 in the absence of Trp. 
B) The antiterminator loop will form in the presence or absence of Trp. 
C) Region 3 will bind to region 4 in and transcription will proceed in the presence or absence of Trp. 
D) Region 3 will bind to region 1 in the presence of Trp. 
A) Region 1 will bind to region 3 in the absence of Trp. 
B) The antiterminator loop will form in the presence or absence of Trp. 
C) Region 3 will bind to region 4 in and transcription will proceed in the presence or absence of Trp. 
D) Region 3 will bind to region 1 in the presence of Trp.

Why is it advantageous for transcription factors to be multimeric and for their binding sites to be clustered?

How do negative regulators such as the Lac repressor prevent RNA polymerase from initiating transcription?

How is glucose involved in catabolite repression of the lac operon?

Catabolic pathways that break down complex substances into more usable units are usually regulated in response to the

In the regulation of the trp operon, tryptophan acts as a(n)

What term describes regulation of the trp operon that can occur even in trpR− mutants, thus suggesting that the mechanism is repressor-independent?

A crucial step in the regulation of most bacterial genes occurs

The transition from transcriptional initiation to elongation involves

Anabolic pathways involved in the synthesis of essential molecules are usually regulated in response to

Proteins whose conformations change when they are bound to an effector molecule are called

Initiation of transcription by RNA polymerase involves the binding of which of the following subunits to the core enzyme?

Transcription and translation can be coupled in bacteria but not eukaryotes because

V.fischeri senses the density of V.fischeri cells in the environment by

Why is the analysis of transcriptomes useful for genetics research?

When RNA-Seq is performed before and after heat shock of bacterial cells, computer analysis would be expected to show

How does a positive regulator affect transcription by RNA polymerase in prokaryotes?

In the trp operon, attenuation occurs through translation of two Trp codons in the leader sequence.What would happen if these two codons were mutated to stop codons?

Genetics: the Study of Biological Information

Mendels Principles of Heredity

Extensions to Mendels Laws

The Chromosome Theory of Inheritance

Linkage, Recombination, and the Mapping of Genes on Chromosomes

DNA Structure, Replication, and Recombination

Anatomy and Function of a Gene: Dissection Through Mutation

Gene Expression: the Flow of Information From Dna to Rna to Protein

Digital Analysis of Dna

Genome Annotation

Analyzing Genomic Variation

The Eukaryotic Chromosome

Chromosomal Rearrangements and Changes in Chromosome Number

Bacterial Genetics

Organellar Inheritance

Gene Regulation in Eukaryotes

Manipulating the Genomes of Eukaryotes

The Genetic Analysis of Development

The Genetics of Cancer

Variation and Selection in Populations

The Genetics of Complex Traits

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Exam 16: Gene Regulation in Prokaryotes

Why is it advantageous for transcription factors to be multimeric and for their binding sites to be clustered?

How do negative regulators such as the Lac repressor prevent RNA polymerase from initiating transcription?

How is glucose involved in catabolite repression of the lac operon?

Catabolic pathways that break down complex substances into more usable units are usually regulated in response to the

In the regulation of the trp operon, tryptophan acts as a(n)

What term describes regulation of the trp operon that can occur even in trpR− mutants, thus suggesting that the mechanism is repressor-independent?

A crucial step in the regulation of most bacterial genes occurs

The transition from transcriptional initiation to elongation involves

Anabolic pathways involved in the synthesis of essential molecules are usually regulated in response to

Proteins whose conformations change when they are bound to an effector molecule are called

Initiation of transcription by RNA polymerase involves the binding of which of the following subunits to the core enzyme?

Transcription and translation can be coupled in bacteria but not eukaryotes because

V.fischeri senses the density of V.fischeri cells in the environment by

Why is the analysis of transcriptomes useful for genetics research?

When RNA-Seq is performed before and after heat shock of bacterial cells, computer analysis would be expected to show

How does a positive regulator affect transcription by RNA polymerase in prokaryotes?

In the trp operon, attenuation occurs through translation of two Trp codons in the leader sequence.What would happen if these two codons were mutated to stop codons?

Genetics: the Study of Biological Information

Mendels Principles of Heredity

Extensions to Mendels Laws

The Chromosome Theory of Inheritance

Linkage, Recombination, and the Mapping of Genes on Chromosomes

DNA Structure, Replication, and Recombination

Anatomy and Function of a Gene: Dissection Through Mutation

Gene Expression: the Flow of Information From Dna to Rna to Protein

Digital Analysis of Dna

Genome Annotation

Analyzing Genomic Variation

The Eukaryotic Chromosome

Chromosomal Rearrangements and Changes in Chromosome Number

Bacterial Genetics

Organellar Inheritance

Gene Regulation in Eukaryotes

Manipulating the Genomes of Eukaryotes

The Genetic Analysis of Development

The Genetics of Cancer

Variation and Selection in Populations

The Genetics of Complex Traits

Filters