Question 1

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

Accepted Answer

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

Question 2

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) ________.

Accepted Answer

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

Question 3

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

Accepted Answer

The answer of For these questions, match the following to...

Question 4

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

Accepted Answer

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

Question 5

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

Accepted Answer

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

Question 6

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

Accepted Answer

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

Question 7

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

Accepted Answer

A) True 
 B)False

Question 8

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

Accepted Answer

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

Question 9

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

Accepted Answer

The answer of For these questions, match the following to...

Question 10

Antisense RNA does which of the following?

Accepted Answer

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

Question 11

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

Accepted Answer

The answer of For these questions, match the following to...

Question 12

What stem-loop conformations favor attenuation?

Accepted Answer

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

Question 13

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

Accepted Answer

A) True 
 B)False

Question 14

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

Accepted Answer

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

Question 15

Repressor proteins are responsible for negative transcriptional regulation.

Accepted Answer

A) True 
 B)False

Question 16

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?

Accepted Answer

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

Question 17

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?

Accepted Answer

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

Question 18

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

Accepted Answer

A) True 
 B)False

Question 19

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

Accepted Answer

A) True 
 B)False

Question 20

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 ________.

Accepted Answer

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

Exam 14: Gene Regulation in Bacteria

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

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

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

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

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

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

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

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

Antisense RNA does which of the following?

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

What stem-loop conformations favor attenuation?

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

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

Repressor proteins are responsible for negative transcriptional regulation.

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 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?

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

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

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 .