Gene Regulation in Bacteria – Ch14 Test Bank | 7e

View Product website:

https://selldocx.com/docx/gene-regulation-in-bacteria-ch14-test-bank-7e-1303

Student name:__________

1) 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

2) Which of the following encode polycistronic mRNA? (Check all that apply.)

A) Lac operon
B) Operator site
C) Trp operon
D) CAP site

3) 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

4) 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

5) How many promoters are in an operon?

A) 1
B) 2
C) 3
D) It depends on how many genes are present in the operon

6) A deletion in an operon removes the terminator. 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

7) 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

8) 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

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

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

10) What stem-loop conformations favor attenuation?

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

11) 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

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

13) In Jacob, Monod, and Pardee's 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

14) 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

15) What would be the result if the U-rich sequence after the 3/4 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

16) 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

17) Enzymes involved in metabolism are most likely regulated via __________.

A) feedbackinhibition
B) acetylation
C) methylation
D) None of these choices are correct.

18) 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

19) The regulation of protein function is called __________.

A) posttranslational regulation
B) transcriptional regulation
C) translational regulation
D) posttranscriptional regulation

20) Translational regulatory proteins recognize specific areas of what molecule?

A) tRNA
B) Ribosome
C) rRNA
D) mRNA

21) 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

22) 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

23) 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/an __________.

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

24) In a particular E. coli strain, a mutation in the thiMD operon results in improper formation of the stem loop secondary structure making it impossible to bind TPP. There are two enzymes encoded by the thiMD operon. How many of the enzymes encoded in the thiMD operon are translated?

A) Two
B) Zero
C) Three
D) One

25) If the Trp codons in the trpL gene were mutated to encode another amino acid, what would the result be?

A) The trp operon would never be transcribed.
B) The trp operon would always be transcribed.
C) The trp operon would only be transcribed when tryptophan in the cell was low.
D) The trp operon would only be transcribed when tryptophan in the cell was high.

26) You are studying riboswitches in different bacterial strains and you mix up two of your samples! One sample is from E. coli and the other is from B. subtilis. You have an assay in the lab that allows you measure the levels of the enzymes encoded by the thi/thiMD operon (assume the enzymes from the two organisms are similar). Would this assay allow you to distinguish between the two strains?

A) Yes - if TPP levels are low and the proteins are produced, the strain is E. coli.
B) Yes - if TPP levels are low and the proteins are produced, the strain is B. subtilis.
C) Yes - if TPP levels are high and the proteins are produced, the strain is E. coli.
D) Yes - if TPP levels are high and the proteins are produced, the strain is B. subtilis.
E) No - it would be difficult to distinguish between the strains using this assay.

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

⊚ true
⊚ false

28) Constitutive genes are those that have constant levels of expression.

⊚ true
⊚ false

29) Negative transcriptional regulation is conducted by activator proteins.

⊚ true
⊚ false

30) Repressor proteins are responsible for negative transcriptional regulation.

⊚ true
⊚ false

31) The term enzyme adaptationis used to describe an enzyme that appears in a living cell following exposure to a specific substrate.

⊚ true
⊚ false

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

⊚ true
⊚ false

33) In the lac operon, the operator site is recognized by an activator protein.

⊚ true
⊚ false

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

⊚ true
⊚ false

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

⊚ true
⊚ false

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

⊚ true
⊚ false

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

⊚ true
⊚ false

38) A riboswitch only affects translation of an operon.

⊚ true
⊚ false