Question 1

What is the difference between a gene that is derepressed and one that is induced?

Accepted Answer

A)  A gene that is derepressed is turned on because a repressor molecule is absent.By comparison,a gene that is induced is turned on because an inducer molecule is present.
B)  A gene that is derepressed is turned on because an inducer molecule is present.By comparison,a gene that is induced is turned on because a repressor molecule is absent.
C)  There is no functional difference between a gene that is derepressed and one that is induced.D) A) and B)
E) A) and C)

Question 2

You are studying the regulation of a prokaryotic operon.Experimental results suggest that the operon is governed by negative control.Based on this information,you conclude that

Accepted Answer

A)  the operon is ON in the absence of its regulatory protein.
B)  the operon is OFF in the absence of its regulatory protein.
C)  the presence of an inducer will always cause a repressor to bind the operator.
D)  the presence of an inducer will always prevent a repressor from binding the operator.E) A) and B)
F) A) and C)

Question 3

Eukaryotic organisms

Accepted Answer

A)  have their transcription occurring in the cytoplasm and translation in the nucleus.
B)  have their transcription occurring in the nucleus and translation in the cytoplasm.
C)  have only operons to assist in gene expression.
D)  carry out protein synthesis only in the presence of the cAMP molecule.
E)  use the leucine zipper primarily for the production of the amino acid tryptophan.F) A) and C)
G) B) and C)

Question 4

A bacterial cell takes advantage of changing __________ conditions through control of gene expression.

Accepted Answer

A)  internal
B)  protein
C)  environmental
D)  geneticE) C) and D)
F) All of the above

Question 5

The DNA-binding proteins of almost all regulatory proteins employ one of a small set of shapes that enable them to fit into the major groove of DNA.These shapes are called

Accepted Answer

A)  structural motifs.
B)  DNA prints.
C)  operons.
D)  repressors.
E)  transcriptional domains.F) A) and D)
G) None of the above

Question 6

The enzyme  β\betaβ -galactosidase acts on lactose to form galactose.In turn,the presence of galactose leads to expression of the enzymes responsible for the metabolism of galactose.In this case,lactose is serving as a carbon source and as a(n)

Accepted Answer

A)  inducer.
B)  repressor.
C)  effector.
D)  operon. E) None of the above
F) A) and B)

Question 7

Mutations in the -35 region of the trp operon would

Accepted Answer

A)  interfere with RNA polymerase binding to the promotor.
B)  prevent the repressor from binding to the operator.
C)  result in depression of the trp operon.
D)  enable the trp operon to be expressed in the absence of tryptophan.E) A) and B)
F) B) and D)

Question 8

Which of the following statements regarding the eukaryotic transcription initiation complex is false?

Accepted Answer

A)  Initiation of transcription of virtually all genes transcribed by RNA pol II require the same suite of general factors.
B)  The transcription initiation transcription complex is responsible for unregulated transcription levels.
C)  The transcription initiation complex can interact with activators through DNA looping.
D)  Basal factors remain associated with RNA pol II after positioning RNA pol II at the start site.E) C) and D)
F) A) and C)

Question 9

Histones are tightly packed into ______,which are located within the DNA.

Accepted Answer

A)  operons
B)  nucleosomes
C)  clusters of proteins
D)  repressor genes
E)  facilitators sitesF) B) and C)
G) A) and E)

Question 10

Regulatory proteins shut off transcription by binding to a site immediately in front of the promoter and often even overlapping the promotor.This site is referred to as the

Accepted Answer

A)  suppressor site.
B)  operator site.
C)  repressor site.
D)  regulatory site.
E)  transcriptional control sitE.F) All of the above
G) C) and D)

Question 11

The CAP molecule can attach to the CAP binding site only when the

Accepted Answer

A)  CAP molecule is bound to lactose.
B)  CAP molecule is bound to tryptophan.
C)  CAP molecule is bound to ATP.
D)  CAP molecule is bound to cAMP.
E)  CAP molecule is activated by homeodomain DNA binding motif.F) A) and C)
G) B) and D) D

Question 12

A cluster of functionally-related genes encoded into a mRNA molecule;a mode of prokaryotic gene regulating unit.

Accepted Answer

A)  operon
B)  repressor
C)  promoter
D)  operator
E)  CAPF) D) and E)
G) None of the above

Question 13

The most common form of regulation in bacteria and eukaryotes is

Accepted Answer

A)  transcriptional control.
B)  translational control.
C)  promotor control.
D)  repressor control.
E)  operator control.F) A) and D)
G) A) and C)

Question 14

In gene regulation,a gene is "turned on" by a(n)

Accepted Answer

A)  activator.
B)  stimulator.
C)  promoter.
D)  regulator.
E)  repressor.F) B) and C)
G) B) and D) A

Question 15

One of the DNA-binding motifs that contains a nearly identical sequence of 60 amino acids in many eukaryotic organisms is known as the

Accepted Answer

A)  non-helical zipper.
B)  leucine zipper.
C)  zinc finger.
D)  homeodomain.
E)  helix-turn-helix.F) All of the above
G) D) and E)

Question 16

A nucleosome contains ____ histones within its core.

Accepted Answer

A)  2
B)  4
C)  6
D)  8
E)  64F) B) and C)
G) All of the above

Question 17

The lac regulatory system is important to bacteria because the sugar lactose

Accepted Answer

A)  cannot be made by bacteria unless the genes are turned on.
B)  is the most common source of food;enzymes are needed all the time.
C)  is only rarely available;producing enzymes all the time is costly.
D)  is incorporated into the nucleic acid of the bacteria.
E)  switches the system off and on whether lactose is present or not.F) None of the above
G) D) and E)

Question 18

The most common form of control of gene expression in both the prokaryotic and eukaryotic organisms is

Accepted Answer

A)  RNA processing control.
B)  translational control.
C)  protein phosphorylation control.
D)  transcriptional control.
E)  mRNA degradation control.F) A) and B)
G) A) and E)

Question 19

The most common DNA-binding motif is the

Accepted Answer

A)  non-helical zipper.
B)  leucine zipper.
C)  zinc finger.
D)  homeodomain.
E)  helix-turn-helix.F) B) and C)
G) A) and B)

Question 20

DNA methylation is the only known natural modification of DNA.It affects

Accepted Answer

A)  adenine bases.
B)  guanine bases.
C)  cytosine bases.
D)  thymine bases.E) A) and B)
F) A) and C) C

Exam 16: Control of Gene Expression

What is the difference between a gene that is derepressed and one that is induced?

Correct AnswerverifiedShow Answer

You are studying the regulation of a prokaryotic operon.Experimental results suggest that the operon is governed by negative control.Based on this information,you conclude that

Correct AnswerverifiedShow Answer

Eukaryotic organisms

Correct AnswerverifiedShow Answer

A bacterial cell takes advantage of changing __________ conditions through control of gene expression.

Correct AnswerverifiedShow Answer

The DNA-binding proteins of almost all regulatory proteins employ one of a small set of shapes that enable them to fit into the major groove of DNA.These shapes are called

Correct AnswerverifiedShow Answer

The enzyme β\betaβ -galactosidase acts on lactose to form galactose.In turn,the presence of galactose leads to expression of the enzymes responsible for the metabolism of galactose.In this case,lactose is serving as a carbon source and as a(n)

Correct AnswerverifiedShow Answer

Mutations in the -35 region of the trp operon would

Correct AnswerverifiedShow Answer

Which of the following statements regarding the eukaryotic transcription initiation complex is false?

Correct AnswerverifiedShow Answer

Histones are tightly packed into ______,which are located within the DNA.

Correct AnswerverifiedShow Answer

Regulatory proteins shut off transcription by binding to a site immediately in front of the promoter and often even overlapping the promotor.This site is referred to as the

Correct AnswerverifiedShow Answer

The CAP molecule can attach to the CAP binding site only when the

Correct AnswerverifiedD

A cluster of functionally-related genes encoded into a mRNA molecule;a mode of prokaryotic gene regulating unit.

Correct AnswerverifiedShow Answer

The most common form of regulation in bacteria and eukaryotes is

Correct AnswerverifiedShow Answer

In gene regulation,a gene is "turned on" by a(n)

Correct AnswerverifiedA

One of the DNA-binding motifs that contains a nearly identical sequence of 60 amino acids in many eukaryotic organisms is known as the

Correct AnswerverifiedShow Answer

A nucleosome contains ____ histones within its core.

Correct AnswerverifiedShow Answer

The lac regulatory system is important to bacteria because the sugar lactose

Correct AnswerverifiedShow Answer

The most common form of control of gene expression in both the prokaryotic and eukaryotic organisms is

Correct AnswerverifiedShow Answer

The most common DNA-binding motif is the

Correct AnswerverifiedShow Answer

DNA methylation is the only known natural modification of DNA.It affects

Correct AnswerverifiedC

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The enzyme $\beta$ -galactosidase acts on lactose to form galactose.In turn,the presence of galactose leads to expression of the enzymes responsible for the metabolism of galactose.In this case,lactose is serving as a carbon source and as a(n)

Correct Answer
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D

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A

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C