Concept: Bacterial Regulation of Gene Expression10m
Concept: The lac Operon10m
Concept: The trp Operon7m
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
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
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
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
Explain why the lac genes are not transcribed in the presence of glucose.
Explain the role of allolactose in regulation of the lac genes.
What is the effect of over-expression of Bcl-2?
A. promote cancer development
B. prevent cancer development
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
Is the absence of the lac repressor sufficient for initiation of transcription of the lac operon?
Can attenuation take place in eukaryotes?
What is an operon? How do operons function in bacteria to control gene transcription?
How is quorum sensing linked to the development of antibiotic resistance?
What are the three different types of horizontal gene transfer? Name, describe and compare them.
Describe mycolic acids. Why is it worth it to Mycobacteria to spend the time it takes to make the chemicals?
Compare and contrast Mycobacteria and Mycoplasma regarding 1) structure, 2) favored location, 3) virulence factors.
During infection, what part of the virus enters a bacterium?
Describe the two ways in which the amino acid tryptophan regulates expression of the trp operon in E. coli.
Why is topoisomerase activity necessary for transcription?
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?
Bacteria divide using _________.
Select the terms on the left to the appropriate blanks on the right to complete the sentences.
List two bacterial cell structures that could also be described as virulence factors and explain.
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?
How do you distinguish bacterial cells that carry a vector from those that do not?
In the absence of glucose, when lactose is present it combines with the repressor, allowing RNA polymerase to carry on transcription.
Operons are found in eukaryotes but not in prokaryotes.
In the presence of tryptophan, transcription of the trp operon is on.
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.
The trp operon consists of ________ genes that encode tryptophan biosynthesis enzymes.
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
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
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
In the Lac operon, the attachment site for RNA polymerase is:
a. The operator
b. The promoter
c. The repressor
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