Deck 14: Gene Regulation in Bacteria and Bacteriophages

Question 1

What stem-loop conformations favor attenuation?

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

Answer 1

D

Question 2

How many promoters are in an operon?

A) 1
B) 2
C) 3
D) Depends on how many genes there are in the operon

Answer 2

A

Question 3

A gene with a strong promoter would be under what type of control?

A) Positive
B) Negative
C) The gene would be expressed constitutively
D) It depends on what the gene encodes

Answer 3

B

Question 4

CAP affects which operon(s)?

A) Ara
B) Trp
C) All of the answers are correct
D) None of the answers are correct

Question 5

Allosteric regulation is accomplished by:

A) A small molecule that fits into an enzyme's active site
B) A large protein that blocks an enzyme's active site
C) A small molecule that fits into a site on the enzyme that is not the active site
D) A small molecule that covalently modifies a site on the enzyme that is not the active site

Question 6

Which of the following is found in an operon?

A) Promoter
B) Terminator
C) Two or more genes
D) Operator
E) All of the answers are correct

Question 7

Which cycle would prevail if there were a mutation in the promoter PRE?

A) Lysogenic
B) Lytic
C) Neither

Question 8

Which promoter(s) activate the cII gene?

A) PL and PR
B) PR and PRE
C) PRM
D) PRM and PRE

Question 9

Enzymes involved in metabolism are most likely regulated via ?

A) Feedback inhibition
B) Acetylation
C) Methylation
D) None of the answers are correct

Question 10

In the same experiment, what would have been the conclusion if all four tubes produced a yellow color when b-ONPG was added?

A) Expression of the lac operon is constitutive whether lacI is functional or not
B) LacI provides the binding site for the repressor
C) LacI encodes a diffusible repressor
D) The researcher added too much b-ONPG

Question 11

What is the gene responsible for attenuation in the trp operon?

A) trpL
B) trpR
C) trpD
D) trpC

Question 12

In Jacob, Monod, and Pardee's experiment, how many functional copies of lacI were there in the merozygote?

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

Question 13

Regulation of gene expression may occur at which of the following levels?

A) Transcription
B) Translation
C) Post translation
D) All of the answers are correct

Question 14

Which of the following encode polycistronic mRNA?

A) Lac operon
B) Ara operon
C) Trp operon
D) All of the answers are correct

Question 15

Which of the following is not an example of 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

Question 16

Which of the following is not associated with positive transcriptional regulation?

A) Activators
B) Inducers
C) Corepressors
D) All of the answers are involved in positive regulation

Question 17

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

Question 18

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

Question 19

What would be the result if the U-rich sequence after the fourth stem loop in the trp operon was replaced by a UG-rich sequence?

A) Attenuation would occur if tryptophan was high
B) Attenuation would occur if tryptophan is low
C) Attenuation would not occur if tryptophan was high
D) None of the answers are correct

Question 20

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) Transcription would be difficult to repress in the presence of glucose

Question 21

Translational regulatory proteins recognize specific areas of what molecule?

A) tRNA
B) Ribosome
C) rRNA
D) mRNA
E) None of the answers are correct

Question 22

The regulation of the CAP complex using cAMP is an example of inducible genetic regulation.

Question 23

Constitutive genes are those that have constant levels of expression.

Question 24

Repressor proteins are responsible for negative transcriptional regulation.

Question 25

Negative transcriptional regulation is conducted by activator proteins.

Question 26

A bacterium is transformed with two plasmids, both containing the same gene. In one, the gene is placed next to a strong promoter and in the other, a weak promoter. How would you expect the two transformed bacteria to grow?

A) The bacteria with the strong promoter would grow slower.
B) The bacteria with the weak promoter would grow slower.
C) Neither bacteria would grow.
D) Both bacteria would grow at the same rate.

Question 27

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

Question 28

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

Question 29

Operons that code for catabolic enzyme systems are typically regulated by repressors.

Question 30

The form of regulation that involves a physical change in the shape of an enzyme is called allosteric
regulation.

Question 31

A temperate phage would be associated with which of the following viral life cycles?

A) Lytic
B) Lysogenic
C) Both life cycles
D) Neither life cycle

Question 32

In the lac operon, the operator site is recognized by a activator protein.

Question 33

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

Question 34

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

Question 35

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

Question 36

The regulation of protein function, not gene expression is called regulation.

A) Posttranslational
B) Transcriptional
C) Translational
D) Post-transcriptional