Question 1

The following are two genotypes of the lactose operon in E. coli:
1)  I+ P+ Oc Z+ Y+
"2)  I- P+ O+ Z+ Y+
Do either of these genotypes produce -galactosidase and permease in the absence of lactose?"

Accepted Answer

A)  Both produce -galactosidase and permease.
B)  Neither produces -galactosidase and permease.
C)  The first one produces -galactosidase and permease; the second does not.
D)  The first one does not produce -galactosidase and permease; the second does.

Question 2

The diagram shown here is part of an RNA transcript containing four open reading frames (M, H, K, and L)  and three introns (1, 2, 3) . The sites labeled d1-d3 are nucleotides immediately before each intron on the 5' side and those labeled a1-a3 are nucleotides immediately after each intron on the 3' side. Splicing out an intron involves cleaving the DNA at the d and a sites at either end of the intron.  A missense mutation takes place in open reading frame K. In which possible alternative splice forms of the transcript would the missense mutation not affect the polypeptide product?

Accepted Answer

A)  d1-a1 + d2-a2 + d3-a3
B)  d1-a2 + d3-a3
C)  d1-a1 + d2-a3
D)  d1-a3
E)  None of the answer options is correct.

Question 3

The diagram shown here is part of an RNA transcript containing four open reading frames (M, H, K, and L)  and three introns (1, 2, 3) .  How many cuts would a spliceosome have to make in order to result in a transcript containing only open reading frames M, K, and L?

Accepted Answer

A)  0
B)  1
C)  2
D)  3
E)  4

Question 4

All CpG sites located near the promoter region of protein coding genes are methylated.

Accepted Answer

A) True 
 B)False

Question 5

A mutant strain of E. coli is found that produces both -galactosidase and permease constitutively. What are the MOST likely mutations in this strain?

Accepted Answer

A)  lacOc
B)  lacI-
C)  lacP-
D)  mutation in CRP-cAMP binding site
E)  lacZ- and lacY-

Question 6

Transcriptional regulation in eukaryotic cells requires the coordinated action of many proteins that interact with one another and with DNA sequences near the gene.

Accepted Answer

A) True 
 B)False

Question 7

Alternative splicing may be considered a mechanism of gene regulation because it:

Accepted Answer

A)  results in DNA rearrangements.
B)  enhances RNA editing.
C)  results in different protein products.
D)  is mutagenic.

Question 8

Which one of the following statements MOST accurately describes methylation?

Accepted Answer

A)  Methyl groups are most often added to cytosines adjacent to guanine bases in or near the promoter sequence, increasing the probability of gene expression.
B)  Methyl groups are most often added to cytosines adjacent to guanine bases in or near the promoter sequence, decreasing the probability of gene expression.
C)  Methyl groups are most often added to adenine-thymine base pairs because they are held by only two hydrogen bonds, and this increases the probability of gene expression.
D)  Methyl groups are most often added to guanine-cytosine base pairs because they are held by three hydrogen bonds, and this decreases the probability of gene expression.
E)  Methyl groups are added to most bases in the promoter region of a specific gene so that RNA polymerase and its associated proteins will bind more efficiently.

Question 9

Nucleosomes occupy fixed positions along the DNA that remain the same over time and in each cell.

Accepted Answer

A) True 
 B)False

Question 10

Transcription in prokaryotes is rapidly turned on or off in response to environmental changes and involves both positive and negative regulators.

Accepted Answer

A) True 
 B)False

Question 11

A virus that infects bacteria is called a:

Accepted Answer

A)  lytic virus.
B)  temperate virus.
C)  lysogenic virus.
D)  bacteriophage.
E)  microphage.

Question 12

Modifications of histone tails can:

Accepted Answer

A)  affect chromatin structure.
B)  activate transcription of some genes.
C)  repress transcription of some genes.
D)  affect expression of some genes in response to the environment.
E)  All of these choices are correct.

Question 13

X-inactivation is caused by the accumulation of:

Accepted Answer

A)  proteins produced by the Xist gene; these proteins induce methylation, histone modification, and other changes associated with preventing transcription.
B)  coding RNA produced by the Xist gene; this RNA, in addition to coding for Xist proteins, binds to and coats the X chromosome undergoing inactivation and physically prevents it from being transcribed.
C)  noncoding RNA produced by the Xist gene, which coats the X chromosome and covalenty crosslinks the DNA strands preventing them from being unwound, "unzipped," and transcribed.
D)  noncoding RNA produced by the Xist gene, which coats the X chromosome and induces DNA methylation, histone modification, and other changes associated with preventing transcription.
E)  None of the answer choices accurately describes the process of X-inactivation.

Question 14

siRNA is a type of _____ RNA.

Accepted Answer

A)  messenger
B)  transfer
C)  ribosomal
D)  splicing
E)  regulatory

Question 15

What does it mean to say that the cI protein establishes a positive feedback loop on its own production?

Accepted Answer

A)  It converts inactive cI protein molecules into active cI molecules.
B)  It stimulates faster translation of the cI messenger RNA.
C)  It makes cI messenger RNA more stable.
D)  It is a positive transcriptional activator of the cI gene.
E)  None of the answer options is correct.

Question 16

A region of prokaryotic DNA consisting of an operator, promoter, and coding sequence for several functionally related genes is called a(n) :

Accepted Answer

A)  closed reading frame.
B)  organized genomic region.
C)  opera.
D)  operon.
E)  operation.

Question 17

Review Figure 19.15 below: -galactosidase and lacY coding sequence for lactose permease are genes called structural genes. B) lacO is a gene sequence coding for the operator. C) The promoter sequence recruits RNA polymerase complex and the initiation of transcription. D) lacI is a gene sequence coding for the repressor which binds to the operator, inhibiting transcription. E) The CRP-cAMP binding site promotes transcription of lactose operon genes if cAMP is high, which indicates that glucose is low and lactose metabolism is needed for energy production." class="answers-bank-image d-inline" rel="preload" > Which one of the following statements about the lactose operon is NOT correct?

Accepted Answer

A)  The lacZ coding sequence for -galactosidase and lacY coding sequence for lactose permease are genes called structural genes.
B)  lacO is a gene sequence coding for the operator.
C)  The promoter sequence recruits RNA polymerase complex and the initiation of transcription.
D)  lacI is a gene sequence coding for the repressor which binds to the operator, inhibiting transcription.
E)  The CRP-cAMP binding site promotes transcription of lactose operon genes if cAMP is high, which indicates that glucose is low and lactose metabolism is needed for energy production.

Question 18

Gene regulation can occur at which of the following steps in the path from DNA to protein?

Accepted Answer

A)  during transcription from a chromosome
B)  during translation from DNA to RNA
C)  after protein synthesis
D)  during transcription from a chromosome and during translation from DNA to RNA
E)  during transcription from a chromosome, during translation from DNA to RNA, and after protein synthesis

Question 19

Using the drawing of mRNA below, choose the letter that BEST fits the description.  The protein-coding region corresponds to region:

Accepted Answer

A)  
A)  
B)  
B)  
C)  
C)  
D)  
D)  
E)  
E)

Question 20

Which of the following statements about transcriptional regulation is INCORRECT?

Accepted Answer

A)  Regulatory transcription factors are proteins that bind to enhancer DNA sequences and then recruit one or more general transcription factors.
B)  A typical gene contains only one enhancer sequence.
C)  General transcription factors are required to initiate the process of transcription.
D)  General transcription factors bind to the TATA box in the promoter region of a gene.
E)  RNA polymerase components are recruited to the promoter region by the general transcription factors bound to the TATA box.

Exam 19: Genetic and Epigenetic Regulation

All CpG sites located near the promoter region of protein coding genes are methylated.

Correct Answer
verified

What does it mean to say that the cI protein establishes a positive feedback loop on its own production?

Correct Answer
verified

Gene regulation can occur at which of the following steps in the path from DNA to protein?

Correct Answer
verified

siRNA is a type of _____ RNA.

Correct Answer
verified

Which of the following statements about transcriptional regulation is INCORRECT?

Correct Answer
verified

Modifications of histone tails can:

Correct Answer
verified

Transcriptional regulation in eukaryotic cells requires the coordinated action of many proteins that interact with one another and with DNA sequences near the gene.

Correct Answer
verified

A region of prokaryotic DNA consisting of an operator, promoter, and coding sequence for several functionally related genes is called a(n) :

Correct Answer
verified

The following are two genotypes of the lactose operon in E. coli: 1) I⁺P⁺O^cZ⁺Y⁺ "2) I^-P⁺O⁺Z⁺Y⁺ Do either of these genotypes produce -galactosidase and permease in the absence of lactose?"

Correct Answer
verified

Nucleosomes occupy fixed positions along the DNA that remain the same over time and in each cell.

Correct Answer
verified

A virus that infects bacteria is called a:

Correct Answer
verified

The diagram shown here is part of an RNA transcript containing four open reading frames (M, H, K, and L) and three introns (1, 2, 3) . How many cuts would a spliceosome have to make in order to result in a transcript containing only open reading frames M, K, and L?

Correct Answer
verified

Which one of the following statements MOST accurately describes methylation?

Correct Answer
verified

Correct Answer
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Review Figure 19.15 below: Which one of the following statements about the lactose operon is NOT correct?

Correct Answer
verified

Alternative splicing may be considered a mechanism of gene regulation because it:

Correct Answer
verified

X-inactivation is caused by the accumulation of:

Correct Answer
verified

Using the drawing of mRNA below, choose the letter that BEST fits the description. The protein-coding region corresponds to region:

Correct Answer
verified

A mutant strain of E. coli is found that produces both -galactosidase and permease constitutively. What are the MOST likely mutations in this strain?

Correct Answer
verified

Transcription in prokaryotes is rapidly turned on or off in response to environmental changes and involves both positive and negative regulators.

Correct Answer
verified

Exam 19: Genetic and Epigenetic Regulation

All CpG sites located near the promoter region of protein coding genes are methylated.

Correct AnswerverifiedShow Answer

What does it mean to say that the cI protein establishes a positive feedback loop on its own production?

Correct AnswerverifiedShow Answer

Gene regulation can occur at which of the following steps in the path from DNA to protein?

Correct AnswerverifiedShow Answer

siRNA is a type of _____ RNA.

Correct AnswerverifiedShow Answer

Which of the following statements about transcriptional regulation is INCORRECT?

Correct AnswerverifiedShow Answer

Modifications of histone tails can:

Correct AnswerverifiedShow Answer

Transcriptional regulation in eukaryotic cells requires the coordinated action of many proteins that interact with one another and with DNA sequences near the gene.

Correct AnswerverifiedShow Answer

A region of prokaryotic DNA consisting of an operator, promoter, and coding sequence for several functionally related genes is called a(n) :

Correct AnswerverifiedShow Answer

The following are two genotypes of the lactose operon in E. coli: 1) I+ P+ Oc Z+ Y+ "2) I- P+ O+ Z+ Y+ Do either of these genotypes produce -galactosidase and permease in the absence of lactose?"

Correct AnswerverifiedShow Answer

Nucleosomes occupy fixed positions along the DNA that remain the same over time and in each cell.

Correct AnswerverifiedShow Answer

A virus that infects bacteria is called a:

Correct AnswerverifiedShow Answer

The diagram shown here is part of an RNA transcript containing four open reading frames (M, H, K, and L) and three introns (1, 2, 3) . How many cuts would a spliceosome have to make in order to result in a transcript containing only open reading frames M, K, and L?

Correct AnswerverifiedShow Answer

Which one of the following statements MOST accurately describes methylation?

Correct AnswerverifiedShow Answer

Correct AnswerverifiedShow Answer

Review Figure 19.15 below: Which one of the following statements about the lactose operon is NOT correct?

Correct AnswerverifiedShow Answer

Alternative splicing may be considered a mechanism of gene regulation because it:

Correct AnswerverifiedShow Answer

X-inactivation is caused by the accumulation of:

Correct AnswerverifiedShow Answer

Using the drawing of mRNA below, choose the letter that BEST fits the description. The protein-coding region corresponds to region:

Correct AnswerverifiedShow Answer

A mutant strain of E. coli is found that produces both -galactosidase and permease constitutively. What are the MOST likely mutations in this strain?

Correct AnswerverifiedShow Answer

Transcription in prokaryotes is rapidly turned on or off in response to environmental changes and involves both positive and negative regulators.

Correct AnswerverifiedShow Answer

Correct Answer
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The following are two genotypes of the lactose operon in E. coli: 1) I⁺P⁺O^cZ⁺Y⁺ "2) I^-P⁺O⁺Z⁺Y⁺ Do either of these genotypes produce -galactosidase and permease in the absence of lactose?"

Correct Answer
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