Question 1

A repressor protein would have which of the following effects on repressible genes with a negative control mechanism?

Accepted Answer

A)   Stimulate transcription in the presence of a corepressor.
B)   Turn off transcription in the presence of an inducer.
C)   Stimulate transcription in the presence of a coactivator.
D)   Turn off transcription in the presence of a corepressor.
E)   A repressor protein does not participate in negative control mechanisms.F) A) and E)
G) A) and D) D

Question 2

The function of the catabolite activator protein (CAP)  is to:

Accepted Answer

A)   increase the affinity of the promoter region for RNA polymerase.
B)   decrease RNA polymerase activity.
C)   deactivate RNA polymerase after binding to AMP.
D)   bind to and activate RNA polymerase directly.
E)   block RNA polymerase from accessing the DNA template.F) None of the above
G) C) and E)

Question 3

Many genes encode proteins that are always needed by a cell, and therefore are always expressed. Such genes are known as:

Accepted Answer

A)   repressible.
B)   promoter.
C)   constitutive.
D)   inducible.
E)   operons.F) B) and C)
G) B) and D)

Question 4

Temporal gene regulation refers to which of the following circumstances?

Accepted Answer

A)   Certain genes are induced only at a particular point in the organism's life cycle.
B)   Certain genes are induced only in specific tissues.
C)   Heat-shock genes are induced during periods of temperature stress.
D)   "Housekeeping" genes are induced in response to a viral infection.
E)   Molecular chaperones are synthesized after heavy-metal ingestion.F) C) and E)
G) B) and C) A

Question 5

DNA sequences called ____ increase the rate of RNA synthesis after initiation of transcription.

Accepted Answer

A)   promoters
B)   TATA boxes
C)   silencers
D)   enhancers
E)   regulatorsF) B) and C)
G) B) and E)

Question 6

Considering that virtually all cells in any given individual contain the same genetic information, how is it possible to have different cell types with unique functions?

Accepted Answer

A)   Gene expression is regulated such that different cell types produce different proteins.
B)   All cells express all proteins encoded in an organism's genes, but turn them on selectively.
C)   Gene expression is regulated based on the age of the organism.
D)   Only some cell types make protein products, while others do not.
E)   Cells lose unneeded genes with each cell division.F) B) and D)
G) A) and E)

Question 7

Some eukaryotic DNA sequences act as introns in the cells of some tissues and exons in the cells of other tissues. This is an example of ____, and allows for ____.

Accepted Answer

A)   positive control; feedback inhibition
B)   gene amplification; the regulation of the rate of transcription
C)   alternative splicing; the formation of different types of closely related proteins
D)   DNA methylation; the formation of different types of closely related proteins
E)   DNA replication; heterodimer formationF) A) and D)
G) B) and D)

Question 8

Bacteria are able to respond quickly to their surroundings, such as in the presence of an abundant food source. This is because:

Accepted Answer

A)   genes for functionally related enzymes are regulated together in operons.
B)   genes for functionally related enzymes are always constitutive.
C)   genes for functionally related enzymes are always under positive control.
D)   efficient protein degradation removes unneeded proteins quickly.
E)   all bacterial genes are constitutive.F) A) and E)
G) B) and C)

Question 9

Genes in euchromatic regions are:

Accepted Answer

A)   transcriptionally inactive.
B)   duplicated
C)   transcriptionally active.
D)   repressed.
E)   unregulated.F) B) and C)
G) All of the above C

Question 10

miRNA-protein complexes regulate gene expression by binding to a target mRNA and preventing translation.

Accepted Answer

A) True 
 B)False

Question 11

The organization of the lac operon, from upstream to downstream sequences, is represented by:

Accepted Answer

A)   repressor gene -> lacZ -> lacY -> lac A
B)   lacZ -> lacY -> lac A
C)   lacZ -> lacY -> lac A -> operator -> promoter
D)   operator -> promoter -> lacZ -> lacY -> lac A
E)   promoter -> operator -> lacZ -> lacY -> lac AF) A) and B)
G) B) and D)

Question 12

Acetyl groups attached to histone tails generally indicate that the genes associated with this nucleosome will be transcriptionally inactive .

Accepted Answer

A) True 
 B)False

Question 13

Eukaryotic transcription factors are best described as:

Accepted Answer

A)   regulators of transcription initiation of operons.
B)   containing only a regulatory domain.
C)   containing only a DNA binding domain.
D)   containing a DNA binding domain plus one or more regulatory domains.
E)   imprinted genes.F) A) and B)
G) A) and D)

Question 14

An activator protein would have which of the following effects on an operon with a positive control mechanism?

Accepted Answer

A)   Stimulate transcription.
B)   Turn off transcription.
C)   Stimulate transcription when a coactivator is bound to the allosteric site.
D)   Inhibit transcription when a coactivator is bound to the allosteric site.
E)   Activator proteins only work on operons under negative control.F) A) and E)
G) C) and E)

Question 15

Sketch the main elements of an inducible operon, such as the lactose operon, and explain the functions of the operator and promoter regions.

Accepted Answer

Concepts to Consider: An operon is a set...

Question 16

Gene expression in bacteria is regulated primarily by:

Accepted Answer

A)   controlling the rate of DNA replication.
B)   protein modifications.
C)   protein degradation.
D)   transcriptional control.
E)   translational control.F) D) and E)
G) A) and E)

Question 17

How does the lactose repressor block transcription of the lactose operon?

Accepted Answer

A)   By "turning off" the lacA intron
B)   By degrading the lacZ protein product
C)   By binding allosterically to the lacZ gene
D)   By slowing the uptake of lactose into the cell
E)   By binding to the operatorF) A) and B)
G) None of the above

Question 18

Figure 14-1  The promoter in the accompanying figure is labeled as ____.

Accepted Answer

A)   6
B)   3
C)   1
D)   2
E)   7F) B) and E)
G) A) and C)

Question 19

Repressible genes are usually actively transcribed when:

Accepted Answer

A)   repressor molecules bind to the promoter.
B)   the end product of the enzymes encoded by these genes is low.
C)   tryptophan accumulates in the cell.
D)   quantities of precursor materials are high.
E)   there is no other substrate that can be used by the cell.F) B) and E)
G) B) and C)

Question 20

In female mammals, most of the inactive X chromosome becomes:

Accepted Answer

A)   associated with histones.
B)   transcriptionally active.
C)   euchromatin.
D)   replicated.
E)   heterochromatin.F) A) and B)
G) D) and E)

Exam 14: Gene Regulation

A repressor protein would have which of the following effects on repressible genes with a negative control mechanism?

Correct AnswerverifiedD

The function of the catabolite activator protein (CAP) is to:

Correct AnswerverifiedShow Answer

Many genes encode proteins that are always needed by a cell, and therefore are always expressed. Such genes are known as:

Correct AnswerverifiedShow Answer

Temporal gene regulation refers to which of the following circumstances?

Correct AnswerverifiedA

DNA sequences called ____ increase the rate of RNA synthesis after initiation of transcription.

Correct AnswerverifiedShow Answer

Considering that virtually all cells in any given individual contain the same genetic information, how is it possible to have different cell types with unique functions?

Correct AnswerverifiedShow Answer

Some eukaryotic DNA sequences act as introns in the cells of some tissues and exons in the cells of other tissues. This is an example of ____, and allows for ____.

Correct AnswerverifiedShow Answer

Bacteria are able to respond quickly to their surroundings, such as in the presence of an abundant food source. This is because:

Correct AnswerverifiedShow Answer

Genes in euchromatic regions are:

Correct AnswerverifiedC

miRNA-protein complexes regulate gene expression by binding to a target mRNA and preventing translation.

Correct AnswerverifiedShow Answer

The organization of the lac operon, from upstream to downstream sequences, is represented by:

Correct AnswerverifiedShow Answer

Acetyl groups attached to histone tails generally indicate that the genes associated with this nucleosome will be transcriptionally inactive .

Correct AnswerverifiedShow Answer

Eukaryotic transcription factors are best described as:

Correct AnswerverifiedShow Answer

An activator protein would have which of the following effects on an operon with a positive control mechanism?

Correct AnswerverifiedShow Answer

Sketch the main elements of an inducible operon, such as the lactose operon, and explain the functions of the operator and promoter regions.

Correct AnswerverifiedConcepts to Consider: An operon is a set...View AnswerShow Answer

Gene expression in bacteria is regulated primarily by:

Correct AnswerverifiedShow Answer

How does the lactose repressor block transcription of the lactose operon?

Correct AnswerverifiedShow Answer

Figure 14-1 The promoter in the accompanying figure is labeled as ____.

Correct AnswerverifiedShow Answer

Repressible genes are usually actively transcribed when:

Correct AnswerverifiedShow Answer

In female mammals, most of the inactive X chromosome becomes:

Correct AnswerverifiedShow Answer

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A

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Some eukaryotic DNA sequences act as introns in the cells of some tissues and exons in the cells of other tissues. This is an example of , and allows for .

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C

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Concepts to Consider: An operon is a set...
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