Bacterial Gene Regulation

Concept: Bacterial Regulation of Gene Expression

10m

Concept: The lac Operon

10m

Concept: The trp Operon

7m

Bacterial Gene Regulation Additional Practice Problems

When arabinose is present and glucose is absent,

A. the ara operon will be turned on by positive control

B. the ara operon will be turned on by negative control

C. the ara operon will be turned off by positive control

D. the ara operon will be turned off by negative control

E. the ara operon will first turn on then turn off

Watch Solution

When the lac operon is turned on, it is said to be under:

A. Regulatory control

B. Negative control

C. Combinatorial control

D. Negative control

Watch Solution

The arginine operon is usually in the _____ position and is _____ by the product.

A. off; repressed

B. on; repressed

C. off; induced

D. on; induced

Watch Solution

The lac operon is usually in the _____ position and is activated by a/an _____ molecule.

A. off, repressor

B. on, repressor

C. off, inducer

D. on, inducer

Watch Solution

 Explain why the lac genes are not transcribed in the presence of glucose. 

Watch Solution

Explain the role of allolactose in regulation of the lac genes.

Watch Solution

What is the effect of over-expression of Bcl-2?

A. promote cancer development

B. prevent cancer development

Watch Solution

What is the function of the product of the galR gene in regulation of the gal operon?

A. A positive regulator of the gal operon

B. A negative regulator of the gal operon

C. Both a positive and a negative regulator of the gal operon

D. Sigma factor required expression the gal operon

Watch Solution

 Is the absence of the lac repressor sufficient for initiation of transcription of the lac operon?

Watch Solution

Can attenuation take place in eukaryotes?

Watch Solution

 What is an operon? How do operons function in bacteria to control gene transcription?

Watch Solution

How is quorum sensing linked to the development of antibiotic resistance?

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What are the three different types of horizontal gene transfer? Name, describe and compare them.

Watch Solution

Describe mycolic acids. Why is it worth it to Mycobacteria to spend the time it takes to make the chemicals?

Watch Solution

Compare and contrast Mycobacteria and Mycoplasma regarding 1) structure, 2) favored location, 3) virulence factors.

Watch Solution

During infection, what part of the virus enters a bacterium?

Watch Solution

Describe the two ways in which the amino acid tryptophan regulates expression of the trp operon in E. coli.

Watch Solution

Why is topoisomerase activity necessary for transcription?

Watch Solution

1. What would happen to transcription of the lac operon in an E. coli cell without a functional CAP protein? What would happen in a cell without a functional lac repressor? 


Watch Solution

Bacteria divide using _________. 


Watch Solution

Select the terms on the left to the appropriate blanks on the right to complete the sentences. 

Watch Solution

List two bacterial cell structures that could also be described as virulence factors and explain.

Watch Solution

What is meant by a repressible operon? In the case of the trp operon, how is repression exerted? If someone asked you to genetically engineer a strain of E. coli to produce large amounts of tryptophan, what would be the easiest way to do that?

Watch Solution

How do you distinguish bacterial cells that carry a vector from those that do not?


Watch Solution

In the absence of glucose, when lactose is present it combines with the repressor, allowing RNA polymerase to carry on transcription.

a. True

b. False

Watch Solution

Operons are found in eukaryotes but not in prokaryotes.

a. True

b. False

Watch Solution

In the presence of tryptophan, transcription of the trp operon is on.

a. True

b. False

Watch Solution

In the absence of tryptophan, the trp repressor is:

a. active and can bind to the operator.

b. active and cannot bind to the operator.

c. inactive and can bind to the operator.

d. inactive and cannot bind to the operator.

 

Watch Solution

The trp operon consists of ________ genes that encode tryptophan biosynthesis enzymes.

a. one

b. two

c. three

d. four

e. five

 

Watch Solution

If E. coli bacteria are grown in the absence of lactose: 

a. The repressor will not bind the operator allowing transcription of the lac operon genes

b. The repressor will bind the operator allowing transcription of the lac operon genes

c. The repressor will not bind the operator preventing transcription of the lac operon genes

d. The repressor will bind the operator preventing transcription of the lac operon gene

Watch Solution

If E. coli bacteria are grown in the presence of lactose: 

a. The repressor will bind the operator allowing transcription of the lac operon genes

b. The repressor will not bind the operator preventing transcription of the lac operon genes

c. The repressor will not bind the operator allowing transcription of the lac operon genes

d. The repressor will bind the operator preventing transcription of the lac operon genes

Watch Solution

In the Lac operon, the protein that binds to the operator to prevent transcription is: 

a. The repressor

b. RNA polymerase

c. DNA polymerase

d. The promoter

e. Lactose

Watch Solution

In the Lac operon, the attachment site for RNA polymerase is: 

a. The operator

b. The promoter

c. The repressor

 

Watch Solution

A group of prokaryotic genes and other segments of DNA that are controlled together is: 

a. A proteome

b. A chromosome

c. A ribosome

d. A replication fork

e. An operon

Watch Solution