Question 1

Which of the following is an example of an epigenetic change?

Accepted Answer

A)   A mutation that changes adenine to guanine
B)   Methylation of a cytosine
C)   The binding of a transcription factor to a sequence of DNA
D)   The mutation of an activator binding site
E)   The mutation of a repressor binding siteF) All of the above
G) B) and E)

Question 2

If glucose and lactose are both abundant,would it be beneficial for E.coli cells to express the genes that metabolize lactose? Why or why not?

Accepted Answer

A)   Yes,because bacteria require both glucose and lactose.
B)   Yes,because it is easier for bacteria to metabolize lactose than glucose.
C)   Yes,because three proteins are required for the uptake and metabolism of lactose.
D)   No,because lactose metabolism requires an inducer.
E)   No,because lactose is broken down into glucose,which is already abundant.F) B) and D)
G) A) and B)

Question 3

The addition of acetyl groups makes histones _______ positively charged,and thus _______ their affinity for DNA.

Accepted Answer

A)   more;increases
B)   more;decreases
C)   less;increases
D)   less;has no effect on
E)   less;decreasesF) A) and E)
G) B) and C)

Question 4

Heterochromatin stains _______ than euchromatin and is _______ transcriptionally active.

Accepted Answer

A)   lighter;more
B)   lighter;less
C)   darker;more
D)   darker;less
E)   darker;just asF) C) and D)
G) All of the above

Question 5

Actin,a protein found in almost all eukaryotic cells,is expressed in most cell types at a fairly constant level.Thus,the gene that codes for actin can be considered a(n) _______ gene.

Accepted Answer

A)   inducible
B)   activated
C)   repressible
D)   constitutive
E)   transcription factorF) All of the above
G) C) and E)

Question 6

A DNA sequence is several thousands of nucleotides distant from the promoter.When this sequence is bound by a protein,transcription rates increase greatly.This sequence is most likely a(n)

Accepted Answer

A)   TATA box.
B)   enhancer.
C)   operon.
D)   promoter.
E)   consensus sequence.F) A) and B)
G) A) and E)

Question 7

In what way does gene regulation differ in eukaryotes and prokaryotes?

Accepted Answer

A)   The prokaryotic RNA polymerase can bind directly to DNA,whereas the eukaryotic polymerase cannot.
B)   The eukaryotic RNA polymerase can bind directly to DNA,whereas the prokaryotic polymerase cannot.
C)   Global gene regulation is absent in prokaryotes.
D)   DNA-protein interactions are involved in gene regulation only in prokaryotes.
E)   Sigma factors are absent in eukaryotes.F) B) and E)
G) B) and D) E

Question 8

What type of molecule is a transcription factor?

Accepted Answer

A)   Protein
B)   Enzyme
C)   DNA
D)   Carbohydrate
E)   LipidF) B) and E)
G) A) and B)

Question 9

Which process is not a control mechanism for regulating the amount of protein synthesized in eukaryotic cells?

Accepted Answer

A)   Breakdown of the synthesized protein
B)   Inhibition of translation with miRNAs
C)   Transcript processing
D)   Transcription regulation
E)   Stabilization of the mRNAF) A) and D)
G) None of the above

Question 10

What is the main difference between general and specific transcription factors?

Accepted Answer

A)   Specific transcription factors are found only in multicellular animals,whereas general transcription factors are found in most eukaryotes.
B)   Specific transcription factors are found only in multicellular plants,whereas general transcription factors are found in most eukaryotes.
C)   Specific transcription factors bind regulatory sequences more tightly than general transcription factors do.
D)   Specific transcription factors bind to regulatory sequences of fewer genes than general transcription factors do.
E)   Specific transcription factors bind regulatory sequences less tightly than general transcription factors do.F) None of the above
G) A) and B) D

Question 11

Two identical twins who showed very similar methylation patterns when they were 4 years old show very divergent patterns at age 40.This divergence is most likely due to

Accepted Answer

A)   different genomic imprinting in the two individuals.
B)   different alternative splicing in the two individuals.
C)   environmental differences that they experienced as adults.
D)   different levels of histone acetyltransferase in the two individuals.
E)   differences in their experiences in utero.F) C) and D)
G) B) and E)

Question 12

The differences between the versions of the Sxl proteins found in male and female Drosophila are generated by the process of

Accepted Answer

A)   methylation.
B)   coordinate regulation.
C)   alternative splicing.
D)   induction.
E)   demethylation.F) A) and E)
G) A) and D) C

Question 13

In what way are HIV and T4 phage similar?

Accepted Answer

A)   They are both retroviruses.
B)   They both (at least initially) rely on the host RNA polymerase to transcribe their genes.
C)   They both produce capsids.
D)   They are both proviruses.
E)   They can both replicate themselves outside a host cell.F) A) and E)
G) A) and D)

Question 14

Which statement about prokaryotes is true?

Accepted Answer

A)   They generally live in static environments.
B)   The most efficient means of regulation of gene expression in these organisms is usually at the posttranslational level.
C)   By making certain proteins only when needed,they save energy and other resources.
D)   They lack the ability to react to their environment through gene expression.
E)   They lack the ability to regulate their gene expression.F) C) and D)
G) A) and C)

Question 15

Suppose that there is a mutation in the lac operon that prevents the repressor from binding to the operator.In the absence of lactose (or allolactose) ,the genes of the operon will be _______.In the presence of lactose (or allolactose) ,the genes will be _______.

Accepted Answer

A)   on;on
B)   on;off
C)   off;on
D)   off;off
E)   None of the above;in both cases the presence or absence of the corepressor would dictate whether the genes are on or off.F) All of the above
G) A) and D)

Question 16

Which statement about transcription factors is true?

Accepted Answer

A)   All transcription factors are repressors.
B)   All transcription factors are activators.
C)   A promoter is a transcription factor.
D)   A transcription factor can be an activator or a repressor.
E)   A transcription factor can be both an activator and a repressor.F) B) and C)
G) All of the above

Question 17

How are inducible and repressible systems similar?

Accepted Answer

A)   Both systems control primarily catabolic pathways.
B)   In both systems,the final product of the pathway usually regulates transcription of the genes that will encode enzymes that produce it.
C)   In both systems,the regulatory molecules function by binding to the operator.
D)   Blocking transcription is the default state for both systems.
E)   Both systems control primarily anabolic pathways.F) B) and E)
G) B) and C)

Question 18

Cyclic AMP,CREB,and protein kinase A are all in the same pathway.What is the correct sequence of these molecules in that pathway (from earliest to latest) ?

Accepted Answer

A)   Cyclic AMP,CREB,protein kinase A
B)   Cyclic AMP,protein kinase A,CREB
C)   CREB,cyclic AMP,protein kinase A
D)   CREB,protein kinase A,cyclic AMP
E)   Protein kinase A,CREB,cyclic AMPF) A) and B)
G) A) and C)

Question 19

In eukaryotic cells,a positive regulator or enhancer

Accepted Answer

A)   binds to the enhancer region to block transcription.
B)   is made of RNA.
C)   binds to an activator protein to increase transcription rates.
D)   is a carbohydrate.
E)   is an enzyme.F) A) and C)
G) C) and E)

Question 20

Many genes involved in the development of animal embryos have similar regulatory sequences.It is likely,therefore,that these

Accepted Answer

A)   sequences bind the same groups of transcription factors.
B)   genes are not regulated together.
C)   genes have the dehydration response element (DR
E)  .
D)   genes are regulated by maternal effect transcription factors.
E)   sequences code for homologous proteins.F) A) and B)
G) A) and C)

Exam 11: Regulation of Gene Expression

Which of the following is an example of an epigenetic change?

Correct AnswerverifiedShow Answer

If glucose and lactose are both abundant,would it be beneficial for E.coli cells to express the genes that metabolize lactose? Why or why not?

Correct AnswerverifiedShow Answer

The addition of acetyl groups makes histones _______ positively charged,and thus _______ their affinity for DNA.

Correct AnswerverifiedShow Answer

Heterochromatin stains _______ than euchromatin and is _______ transcriptionally active.

Correct AnswerverifiedShow Answer

Actin,a protein found in almost all eukaryotic cells,is expressed in most cell types at a fairly constant level.Thus,the gene that codes for actin can be considered a(n) _______ gene.

Correct AnswerverifiedShow Answer

A DNA sequence is several thousands of nucleotides distant from the promoter.When this sequence is bound by a protein,transcription rates increase greatly.This sequence is most likely a(n)

Correct AnswerverifiedShow Answer

In what way does gene regulation differ in eukaryotes and prokaryotes?

Correct AnswerverifiedE

What type of molecule is a transcription factor?

Correct AnswerverifiedShow Answer

Which process is not a control mechanism for regulating the amount of protein synthesized in eukaryotic cells?

Correct AnswerverifiedShow Answer

What is the main difference between general and specific transcription factors?

Correct AnswerverifiedD

Two identical twins who showed very similar methylation patterns when they were 4 years old show very divergent patterns at age 40.This divergence is most likely due to

Correct AnswerverifiedShow Answer

The differences between the versions of the Sxl proteins found in male and female Drosophila are generated by the process of

Correct AnswerverifiedC

In what way are HIV and T4 phage similar?

Correct AnswerverifiedShow Answer

Which statement about prokaryotes is true?

Correct AnswerverifiedShow Answer

Suppose that there is a mutation in the lac operon that prevents the repressor from binding to the operator.In the absence of lactose (or allolactose) ,the genes of the operon will be _______.In the presence of lactose (or allolactose) ,the genes will be _______.

Correct AnswerverifiedShow Answer

Which statement about transcription factors is true?

Correct AnswerverifiedShow Answer

How are inducible and repressible systems similar?

Correct AnswerverifiedShow Answer

Cyclic AMP,CREB,and protein kinase A are all in the same pathway.What is the correct sequence of these molecules in that pathway (from earliest to latest) ?

Correct AnswerverifiedShow Answer

In eukaryotic cells,a positive regulator or enhancer

Correct AnswerverifiedShow Answer

Many genes involved in the development of animal embryos have similar regulatory sequences.It is likely,therefore,that these

Correct AnswerverifiedShow Answer

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The addition of acetyl groups makes histones _ positively charged,and thus _ their affinity for DNA.

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Heterochromatin stains _ than euchromatin and is _ transcriptionally active.

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E

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D

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C

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Suppose that there is a mutation in the lac operon that prevents the repressor from binding to the operator.In the absence of lactose (or allolactose) ,the genes of the operon will be _.In the presence of lactose (or allolactose) ,the genes will be _.

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