Question 1

A repressible operon is usually controlled by:

Accepted Answer

A)   an inactive repressor that allows it to be in the "on" state.
B)   the supply of the precursor product for the enzymes.
C)   an inactive repressor that keeps it in the "off" state.
D)   tryptophan.
E)   being turned "on," usually by the end product of the pathway.F) C) and E)
G) All of the above

Question 2

Temporal gene regulation refers to which of the following circumstances?

Accepted Answer

A)   Certain genes are induced only at a particular point in the 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) A) and B)
G) None of the above

Question 3

In the tryptophan operon, the repressor actively binds to the operator when:

Accepted Answer

A)   tryptophan binds to an allosteric site on the repressor.
B)   tryptophan levels are low.
C)   lactose levels are low.
D)   there is a great need for proteins.
E)   allotryptophan levels are low.F) A) and E)
G) B) and C)

Question 4

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

Accepted Answer

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

Question 5

Explain the respective advantages associated with operons being inducible (e.g., the lactose operon) or repressible (e.g., the tryptophan operon).

Accepted Answer

Inducible operons save energy for the prokaryotes because the proteins of the operon are only synthesized when needed for survival.
The advantage of a repressible operons is that they prevent excess production of a metabolite.

Question 6

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

Accepted Answer

A)   by "turning off" the appropriate genes in the intron
B)   by regulating the activity of the enzymes that the operon codes for
C)   by binding allosterically to the appropriate genes
D)   by slowing the uptake of lactose into the cell
E)   by binding to the operatorF) None of the above
G) D) and E)

Question 7

Regulation of gene expression can NOT be accomplished by controlling:

Accepted Answer

A)   the activity of a protein product.
B)   the amount of mRNA that is available.
C)   the rate of translation of mRNA.
D)   the rate of mRNA degradation.
E)   the rate of DNA replicationF) A) and E)
G) A) and D)

Question 8

A repressor operon regulates the gene expression of anabolic pathways.
__________________

Accepted Answer

A) True 
 B)False  True

Question 9

Some eukaryotic DNA sequences act as introns in the cells of some tissues and exons in the cells of other tissues.This allows:

Accepted Answer

A)   prevention of harmful mutation.
B)   regulation of the rate of transcription.
C)   formation of different types of closely related proteins.
D)   regulation of the rate of translation.
E)   repression of DNA replication.F) C) and D)
G) A) and B)

Question 10

MATCHING
Match the type of gene regulation with the process.
a.regulation of transcription
d.regulation of translation
b.regulation of mRNA processing
e.regulation of chromatin
c.regulation of mRNA transport
-Controlling access to nuclear pores

Accepted Answer

The answer of MATCHING
Match the type of gene regulation with...

Question 11

Mutations in the TATA box increase the rate of transcription.
__________________

Accepted Answer

A) True 
 B)False

Question 12

Genes in euchromatic regions are:

Accepted Answer

A)   inhibited.
B)   duplicated
C)   actively being transcribed.
D)   repressed.
E)   unregulated.F) A) and E)
G) B) and D)

Question 13

MATCHING
Match the type of gene regulation with the process.
a.regulation of transcription
d.regulation of translation
b.regulation of mRNA processing
e.regulation of chromatin
c.regulation of mRNA transport
-Unpacked heterochromatin

Accepted Answer

The answer of MATCHING
Match the type of gene regulation with...

Question 14

Feedback inhibition is:

Accepted Answer

A)   transcriptional control.
B)   transcriptional control
C)   a mechanism affecting events after translation.
D)   a repressible system.
E)   constitiutive controlF) A) and B)
G) B) and D)

Question 15

The operator of the lactose operon in E.coli is located:

Accepted Answer

A)   between the promoter and the TATA box.
B)   upstream of the promoter.
C)   between the promoter and the structural genes.
D)   among the structural genes.
E)   anywhere on the chromosome.F) B) and C)
G) A) and E) C

Question 16

An inducible operon is usually controlled by:

Accepted Answer

A)   an inducer molecule that keeps it in the "off" state.
B)   an active repressor that keeps it in the "off" state.
C)   being active at all times.
D)   allolactose.
E)   being turned "off," usually by the end product of the pathway.F) B) and E)
G) A) and D)

Question 17

A cell may meet the need for large quantities of a specific protein by all of the following EXCEPT :

Accepted Answer

A)   continuously synthesizing the mRNA molecule that specifies that protein.
B)   increasing the half-life of the mRNA that specifies the protein.
C)   having multiple copies of the gene that codes for that protein.
D)   amplifying protein genes by DNA replication
E)   inhibition of DNA synthesisF) A) and D)
G) A) and E)

Question 18

Why is it important that a few $\beta$-galactosidase molecules be present in E.coli even if these cells have been growing on a lactose-free medium?

Accepted Answer

Concepts to Consider: It is im...

Question 19

The gene that codes for the repressor protein of the E.coli lactose operon is:

Accepted Answer

A)   located between the operator and the promoter.
B)   downstream from the promoter region.
C)   downstream from the operator.
D)   constitutive.
E)   turned off most of the time.F) A) and C)
G) C) and D)

Question 20

In female mammals, most of the inactive X chromosome has become:

Accepted Answer

A)   associated with histones.
B)   active X factor.
C)   euchromatin.
D)   replicated.
E)   heterochromatin.F) All of the above
G) A) and B)

Exam 14: Gene Regulation

A repressible operon is usually controlled by:

Correct AnswerverifiedShow Answer

Temporal gene regulation refers to which of the following circumstances?

Correct AnswerverifiedShow Answer

In the tryptophan operon, the repressor actively binds to the operator when:

Correct AnswerverifiedShow Answer

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

Correct AnswerverifiedShow Answer

Explain the respective advantages associated with operons being inducible (e.g., the lactose operon) or repressible (e.g., the tryptophan operon).

Correct AnswerverifiedInducible operons save energy for the prokaryotes because the proteins of the operon are only synthesized when needed for survival. The advantage of a repressible operons is that they prevent excess production of a metabolite.

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

Correct AnswerverifiedShow Answer

Regulation of gene expression can NOT be accomplished by controlling:

Correct AnswerverifiedShow Answer

A repressor operon regulates the gene expression of anabolic pathways. __________________

Correct AnswerverifiedTrue

Some eukaryotic DNA sequences act as introns in the cells of some tissues and exons in the cells of other tissues.This allows:

Correct AnswerverifiedShow Answer

MATCHING Match the type of gene regulation with the process. a.regulation of transcription d.regulation of translation b.regulation of mRNA processing e.regulation of chromatin c.regulation of mRNA transport -Controlling access to nuclear pores

Correct AnswerverifiedShow Answer

Mutations in the TATA box increase the rate of transcription. __________________

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Genes in euchromatic regions are:

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MATCHING Match the type of gene regulation with the process. a.regulation of transcription d.regulation of translation b.regulation of mRNA processing e.regulation of chromatin c.regulation of mRNA transport -Unpacked heterochromatin

Correct AnswerverifiedShow Answer

Feedback inhibition is:

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The operator of the lactose operon in E.coli is located:

Correct AnswerverifiedC

An inducible operon is usually controlled by:

Correct AnswerverifiedShow Answer

A cell may meet the need for large quantities of a specific protein by all of the following EXCEPT :

Correct AnswerverifiedShow Answer

Why is it important that a few β\betaβ -galactosidase molecules be present in E.coli even if these cells have been growing on a lactose-free medium?

Correct AnswerverifiedConcepts to Consider: It is im...View AnswerShow Answer

The gene that codes for the repressor protein of the E.coli lactose operon is:

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In female mammals, most of the inactive X chromosome has become:

Correct AnswerverifiedShow Answer

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Inducible operons save energy for the prokaryotes because the proteins of the operon are only synthesized when needed for survival. The advantage of a repressible operons is that they prevent excess production of a metabolite.

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True

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C

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Why is it important that a few $\beta$ -galactosidase molecules be present in E.coli even if these cells have been growing on a lactose-free medium?

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Concepts to Consider: It is im...
View Answer

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