Microbiology Multiple Choice Questions on “Bacterial Transduction”.
1. How much time is taken by the new DNA to make whole phage particles?
A. 24 hours
B. 60 mins
C. 2 mins
D. 10-20 mins
Answer: D
Clarification: Within 10 to 20 minutes, depending on the phage, the new DNA combines with the new proteins to make whole phage particles, which are released by the destruction of the cell wall and lysis of the cell.
2. When viral genome can become integrated into the bacterial genome they are known as ____________
A. temperate phage
B. prophage
C. bacteriophage
D. episome
Answer: B
Clarification: When viral genome can become integrated into the bacterial genome they are known as prophages. They carry DNA that can behave as a kind of episome in bacteria.
3. Bacteriophages inject their nucleic acid into the bacterium.
A. True
B. False
Answer: A
Clarification: Bacteriophages inject their nucleic acid usually DNA into the bacterium where it replicates rapidly and also directs the synthesis of new phage proteins.
4. Which of the following role is performed by a bacteriophage in transduction?
A. vector
B. donor
C. recipient
D. episome
Answer: A
Clarification: Bacterial transduction is the transfer by a bacteriophage, serving as a vector, of a portion of DNA from one bacterium (donor) to another (a recipient).
5. The viral DNA may be incorporated into the phage head during phage assembly.
A. True
B. False
Answer: B
Clarification: Any part of the bacterial chromosome may be incorporated into the phage head during phage assembly and is usually not associated with any viral DNA.
6. What is the frequency of defective phage particles in progeny phage produced?
A. 100
B. 10-1
C. 10-5
D. 1000
Answer: C
Clarification: The frequency of such defective phage particles is about 10-5 to 10-7 of the progeny phage produced.
7. Fragments transferred by a bacteriophage contains how many genes?
A. 20
B. 50
C. 1
D. 100
Answer: D
Clarification: Generalized transduction provides a means for mapping bacterial genes, since the fragments transferred by a bacteriophage are often large enough to contain 100s of genes.
8. What is the correct order when coliphage P1 is grown in a thr+ leu+ aziR host is used to infect a thr- leu- azi- recipient bacterial cell?
A. thr+ leu+ aziR
B. thr– leu+ aziR
C. thr+ leu– aziR
D. thr– leu– aziR
Answer: A
Clarification: When coliphage P1 is grown in a thr+ leu+ aziR host is used to infect a thr– leu– azi– recipient bacterial cell then if Leu+ recombinants are selected, about 50 percent of these are also AzR.
9. How many percent of thr+ transducing phages also carry leu+?
A. 10%
B. 5%
C. 3%
D. 15%
Answer: C
Clarification: Only 3% of thr+ transducing phages also carry leu+ shows that these two genes are so far apart that they are rarely included at the same time in a DNA fragment that goes into the P1 head.
10. When the phage transduces only those bacterial genes adjacent to the prophage in the bacterial chromosome then it is known as?
A. generalized transduction
B. specialized transduction
C. restricted transduction
D. conjugation
Answer: C
Clarification: When the phage transduces only those bacterial genes adjacent to the prophage in the bacterial chromosome then it is known as restricted transduction.
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