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Operons that code for anabolic enzyme systems are typically regulated by inducers.

A) True
B) False

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Repressor proteins are responsible for negative transcriptional regulation.

A) True
B) False

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If CAP could not bind to its CAP site, then what would be the result? Assume lactose is present in each scenario.


A) Transcription would be difficult to repress in the presence of glucose
B) Transcription would be difficult to activate in the presence of glucose
C) Transcription would be difficult to activate in the absence of glucose

D) All of the above
E) B) and C)

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A mutation in the lacI gene prevents the gene product from binding allolactose. What will the expression level of the operon be in the absence of lactose?


A) no transcription
B) positive regulation
C) constitutively active
D) transcription will occur only in the presence of glucose

E) B) and C)
F) A) and B)

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The term enzyme adaptation is used to describe an enzyme that appears in a living cell following exposure to a specific substrate.

A) True
B) False

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Which of the following is an example of post translational regulation in prokaryotes?


A) Sterically blocking the ribosome
B) Phosphorylation of an enzyme
C) Incorporation of antisense RNA
D) Altering the structure of the mRNA

E) A) and D)
F) All of the above

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Antisense RNA does which of the following?


A) Inhibits the formation of the open complex in transcription
B) Occupies the A and P sites of the ribosome
C) Binds to the mRNA and prevents translation
D) Prevents the correct folding of a newly formed peptide

E) C) and D)
F) B) and C)

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An enzyme catalyzes a substrate into a final product. When the concentration of the final product is high enough, it binds to a regulatory site on the enzyme. This binding at the regulatory site changes the shape of the enzyme, which prevents it from binding the substrate and prevents formation of more final product. This is an example of a(n) ________.


A) posttranslational modification
B) allosteric enzyme
C) translational repressor
D) methylation

E) A) and B)
F) C) and D)

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For these questions, match the following to its appropriate letter. Use each letter only once. A) lacI gene product B) Operator C) Allolactose D) Lac operon E) Trp operon F) Tryptophan -Inducible

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In the lac operon, the operator is an example of a trans-effect genetic regulation.

A) True
B) False

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A deletion in an operon removes the promoter. How will that affect the transcript that is produced from the operon?


A) The transcript will be produced and normal in length
B) The transcript will be produced, but shorter than normal
C) The transcript will be produced, but longer than normal
D) The transcript will produced, but will contain a deletion
E) The transcript will not be produced

F) B) and E)
G) A) and D)

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What stem-loop conformations favor attenuation?


A) 1-2
B) 1-2 and 2-3
C) 2-3
D) 1-2 and 3-4

E) All of the above
F) C) and D)

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A gene is inducible and under negative control. Which of the following pairs will allow expression of this gene?


A) Activator + repressor
B) Activator + inhibitor
C) Repressor + inducer
D) Repressor + co-repressor

E) A) and C)
F) None of the above

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Regulation of gene expression may occur at which of the following levels? Check all that apply.


A) post translation
B) constitutive expression
C) translation
D) transcription

E) None of the above
F) All of the above

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DNA that contains instructions for two or more structural genes produces monocistronic mRNA.

A) True
B) False

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For these questions, match the following to its appropriate letter. Use each letter only once. A) lacI gene product B) Operator C) Allolactose D) Lac operon E) Trp operon F) Tryptophan -Co-repressor

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For these questions, match the following to its appropriate letter. Use each letter only once. A) lacI gene product B) Operator C) Allolactose D) Lac operon E) Trp operon F) Tryptophan -Trans-acting element

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In the lac operon, the CAP site is located next to the ________. When both lactose and glucose are present, this leads to a rate of transcription that is ________.


A) terminator, low
B) promoter, high
C) terminator, high
D) promoter, low

E) C) and D)
F) A) and D)

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An activator is present and results in the increase in transcription of the target gene. This is an example of ________.


A) termination
B) positive control
C) negative control
D) feedback inhibition

E) B) and C)
F) All of the above

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If a bacteria is placed in an environment that contains both glucose and lactose, the regulation of the lac operon will allow which nutrient to be processed first?


A) Glucose
B) Lactose
C) Both will be processed equally
D) Neither will be processed in this environment

E) A) and B)
F) All of the above

Correct Answer

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