Question 1

The binding of the inducer to the repressor causes the repressor to

Accepted Answer

A)   bind to the operator.
B)   stop binding to the operator.
C)   bind to the structural genes.
D)   stop binding to the structural genes.
E)   bind to other repressors.

Question 2

Alternative splicing is controlled by

Accepted Answer

A)   regulatory elements in the RNA sequence that bind specific proteins alone.
B)   miRNA alone.
C)   secondary RNA structures alone.
D)   miRNA and regulatory elements in the RNA sequence that bind specific proteins.
E)   regulatory elements in the RNA sequence that bind specific proteins and secondary RNA structures.

Question 3

A strain of HIV has more termination of partial transcripts than is typical.The most likely cause is a mutation

Accepted Answer

A)   that causes tat protein to be somewhat more able to bind to RNA.
B)   that causes tat protein to be somewhat less able to bind to RNA.
C)   that causes reverse transcriptase to be more active.
D)   that causes reverse transcriptase to be less active.
E)   in a protease that increases its activity.

Question 4

Conferring of epigenetic patterns onto offspring is called genomic imprinting.Genomic imprinting would likely be most affected by globally inhibiting the gene(s)  for

Accepted Answer

A)   expression of the Xist RNA.
B)   DNA methyltransferase and DNA demethyltransferase.
C)   histone deacetylase.
D)   a splicing factor.
E)   miRNA processing nuclease.

Question 5

A certain enzyme is synthesized whenever the solution in which cells are growing contains substance X.This phenomenon is most likely an example of a(n)  _______ system.

Accepted Answer

A)   positive
B)   inducible
C)   repressible
D)   negative
E)   positive-negative

Question 6

In a fruit fly, the transcription rates of a gene that codes for an enzyme vary tremendously among different cell types.The most likely reason for these differences is that different cell types have different

Accepted Answer

A)   promoters.
B)   inducers.
C)   transcription factors present.
D)   silencers.
E)   enhancers.

Question 7

Which term would be associated with a prophage?

Accepted Answer

A)   HIV
B)    in lytic phase
C)    in lysogenic phase
D)   A bacterial cell when the lac operon is turned on
E)   A bacterial cell when the lac operon is turned off

Question 8

Suppose lactose is in high concentration and glucose is in low concentration in the surrounding media, yet the cell is not taking in much lactose.The lactose that is taken in is quickly metabolized.The most likely explanation for this is a mutation in

Accepted Answer

A)   the gene coding for β-galactoside.
B)   the gene coding for β-galactoside permease.
C)   the gene coding for β-galactoside transacetylase.
D)   the operator.
E)   the promoter.

Question 9

Which genes would be considered to be composed of heterochromatin?

Accepted Answer

A)   Ribosomal genes
B)   Genes that encode for RNA polymerase
C)   Genes that encode for DNA polymerase
D)   Genes in Barr bodies
E)   Structural genes under active transcription

Question 10

A strain of bacteria prefers to metabolize fructose, but it can grow on other sugars.When fructose is abundant, the expression of genes involved in metabolizing other sugars is much reduced.This is an example of _______.

Accepted Answer

catabolite...

Question 11

In the treatment of HIV, _______ are used because they block synthesis of viral DNA from RNA.

Accepted Answer

reverse tr...

Question 12

Some viruses can cause cancer in the long term by allowing progression through the cell cycle.This could be due to labeling of certain cell cycle checkpoint molecules with _______, targeting them for the proteasome.

Accepted Answer

The answer of Some viruses can cause cancer in the...

Question 13

A cue for the switch from lysogenic phase to lytic phase of a virus would involve _______.

Accepted Answer

environmen...

Question 14

All cells in a given mammal carry the same genome, yet certain genes are expressed only in a particular tissue, such as in the eye, and not expressed in other tissues, such as in the liver.How is this specificity of gene expression for a particular tissue achieved?

Accepted Answer

A)   Different tissues inactivate whole swaths of the genome, like a Barr body, thereby achieving tissue-specific gene expression.
B)   Different tissues express unique transcription factors that are bound to tissue-specific enhancer elements, thereby achieving tissue-specific gene expression.
C)   All different cell types in the organism express all proteins equally and degrade the proteins that they don't need.
D)   Certain organ and tissue systems, such as the nervous system, form relatively early in the organism's embryonic life, as compared to the epidermis; it is this relative age of the tissue lineage that determines which tissue-specific genes are expressed.
E)   Each tissue has a unique RNA polymerase holoenzyme that achieves tissue-specific gene expression.

Question 15

Suppose that in a strain of mice, specific bases on DNA are methylated but that these methylation changes are not stable and are erased before they can be passed on to the next generation.The name of the enzyme that is made defective in these mice is most likely _______.

Accepted Answer

maintenanc...

Question 16

What would happen initially to cells that lack a functional ubiquitin?

Accepted Answer

A)   Nothing would happen.
B)   Transcriptional initiation would increase.
C)   Protein degradation would decrease.
D)   Histone modifications would increase.
E)   Translation of proteins would be more efficient.

Question 17

A herpes virus causes both chicken pox and shingles in humans.People who have had chicken pox may be afflicted with shingles much later in life.The most likely explanation for this is that

Accepted Answer

A)   the intact virus was harbored within cells and was activated.
B)   the viral DNA had been incorporated into the host's genome and was later induced to enter the lytic phase.
C)   the viral DNA had been incorporated into the host's genome and was later induced to enter the lysogenic phase.
D)   the viral DNA became active while integrated into the host's DNA.
E)   expression of host DNA genes was shut down.

Question 18

A protein-coding gene in a eukaryote has four exons and three introns in the following arrangement.  Assuming that transcription begins at exon 1 and ends after exon 4, how many different proteins could be made by alternative splicing of the pre-mRNA from this gene?

Accepted Answer

A)   Two
B)   Three
C)   Four
D)   Five
E)   Six

Question 19

Which molecule acts as a co-repressor to block transcription of the tryptophan operon?

Accepted Answer

A)   cAMP
B)   Lactose
C)   Tryptophan
D)   Methionine
E)   CRP

Question 20

DNA in eukaryotes is wrapped around special proteins to form structures that look like beads on a string.These structures are called _______.

Accepted Answer

The answer of DNA in eukaryotes is wrapped around special...

Exam 16: Regulation of Gene Expression

A strain of bacteria prefers to metabolize fructose, but it can grow on other sugars.When fructose is abundant, the expression of genes involved in metabolizing other sugars is much reduced.This is an example of _______.

Correct Answerverifiedcatabolite...View AnswerShow Answer

In the treatment of HIV, _______ are used because they block synthesis of viral DNA from RNA.

Correct Answerverifiedreverse tr...View AnswerShow Answer

What would happen initially to cells that lack a functional ubiquitin?

Correct AnswerverifiedShow Answer

Which molecule acts as a co-repressor to block transcription of the tryptophan operon?

Correct AnswerverifiedShow Answer

A protein-coding gene in a eukaryote has four exons and three introns in the following arrangement. Assuming that transcription begins at exon 1 and ends after exon 4, how many different proteins could be made by alternative splicing of the pre-mRNA from this gene?

Correct AnswerverifiedShow Answer

A cue for the switch from lysogenic phase to lytic phase of a virus would involve _______.

Correct Answerverifiedenvironmen...View AnswerShow Answer

A strain of HIV has more termination of partial transcripts than is typical.The most likely cause is a mutation

Correct AnswerverifiedShow Answer

Some viruses can cause cancer in the long term by allowing progression through the cell cycle.This could be due to labeling of certain cell cycle checkpoint molecules with _______, targeting them for the proteasome.

Correct AnswerverifiedShow Answer

The binding of the inducer to the repressor causes the repressor to

Correct AnswerverifiedShow Answer

Suppose lactose is in high concentration and glucose is in low concentration in the surrounding media, yet the cell is not taking in much lactose.The lactose that is taken in is quickly metabolized.The most likely explanation for this is a mutation in

Correct AnswerverifiedShow Answer

Which genes would be considered to be composed of heterochromatin?

Correct AnswerverifiedShow Answer

Which term would be associated with a prophage?

Correct AnswerverifiedShow Answer

Alternative splicing is controlled by

Correct AnswerverifiedShow Answer

In a fruit fly, the transcription rates of a gene that codes for an enzyme vary tremendously among different cell types.The most likely reason for these differences is that different cell types have different

Correct AnswerverifiedShow Answer

A herpes virus causes both chicken pox and shingles in humans.People who have had chicken pox may be afflicted with shingles much later in life.The most likely explanation for this is that

Correct AnswerverifiedShow Answer

A certain enzyme is synthesized whenever the solution in which cells are growing contains substance X.This phenomenon is most likely an example of a(n) _______ system.

Correct AnswerverifiedShow Answer

All cells in a given mammal carry the same genome, yet certain genes are expressed only in a particular tissue, such as in the eye, and not expressed in other tissues, such as in the liver.How is this specificity of gene expression for a particular tissue achieved?

Correct AnswerverifiedShow Answer

DNA in eukaryotes is wrapped around special proteins to form structures that look like beads on a string.These structures are called _______.

Correct AnswerverifiedShow Answer

Conferring of epigenetic patterns onto offspring is called genomic imprinting.Genomic imprinting would likely be most affected by globally inhibiting the gene(s) for

Correct AnswerverifiedShow Answer

Suppose that in a strain of mice, specific bases on DNA are methylated but that these methylation changes are not stable and are erased before they can be passed on to the next generation.The name of the enzyme that is made defective in these mice is most likely _______.

Correct Answerverifiedmaintenanc...View AnswerShow Answer

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catabolite...
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reverse tr...
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