Vector Biology Multiple Choice Questions on “Single Stranded DNA Vectors Cloning – 1”.
1. Which of the following is not a filamentous coliphage vector?
A. M13
B. Lambda
A. F1
D. Fd
Answer: B
Clarification: M13, F1, FD are filamentous coliphages containing a circular single-stranded DNA molecule. These have been developed as vectors because of various advantages.
2. Coliphages are single-stranded vectors.
A. True
B. False
Answer: A
Clarification: M13, F1, FD are filamentous coliphages containing a circular single-stranded DNA molecule. These have been developed as vectors because of various advantages.
3. What is the average size of single-stranded vector?
A. 6400 nucleotides
B. 1200 nucleotides
A. 2500 nucleotides
D. 5500 nucleotides
Answer: A
Clarification: The phage particles have dimensions 900*9 nm and contain a single-stranded circular DNA molecule, which is 6407 (M13) or 6408 (fD).
4. The complete nucleotide sequences of fD and M13 are ___ percent identical.
A. 25
B. 97
A. 40
D. 65
Answer: B
Clarification: The complete nucleotide sequences of fd and M13 are available and they are 97 percent identical. The difference is mainly in isolated nucleotides.
5. The filamentous single-stranded phages infect only _________________
A. Fungi
B. Mammals
A. Plants
D. Enteric bacteria
Answer: D
Clarification: The filamentous phages only infect strains of enteric bacteria harboring F pili. The adsorption site appears to be the end of the F pilus.
6. How many phage particles are released per generation upon coliphage infection?
A. 10
B. 100
A. 500
D. 1000
Answer: D
Clarification: Replication of phage DNA does not result in host lysis. Infected cells grow albeit at a slower rate. Around 1000 phage particles may be released into the medium.
7. Phage DNA enters the cell by a process in which ________ and replication are tightly coupled.
A. Encapsulation
B. Decapsidation
A. Translation
D. Transcription
Answer: B
Clarification: The single stranded phage DNA enters the cell by a process in which decapsidation and replication are tightly coupled. Conversion to RF takes place.
8. What is RF?
A. Plasmid
B. Coliphage
A. Replicative form
D. Hybrid vector
Answer: C
Clarification: The capsid proteins enter the cytoplasmic membrane as the viral DNA passes into the cell while being converted to a double-stranded replicative form.
9. The RF multiplies ________
A. Slowly
B. Rapidly
A. Moderately
D. Does not multiply
Answer: B
Clarification: The capsid proteins enter the cytoplasmic membrane as the viral DNA passes into the cell while being converted to a double-stranded replicative form. RF replicates rapidly.
10. What happens following the morphogenesis of the cell?
A. Progeny strands release
B. DNA replication
A. Host lysis
D. Degradation
Answer: A
Clarification: The progeny single strands are synthesized and released from the cell as filamentous particles the following morphogenesis at the cell membrane.
11. Dominant selectable markers can be used with __________
A. Any cell type
B. Mutant cells
A. Wild-type cells
D. Recombinant cells
Answer: A
Clarification: Endogenous markers are largely superseded by so-called dominant selectable markers, which confer a phenotype that is entirely novel to the cell and can hence be used in any cell type.
12. What are dominant selectable markers?
A. Drug-resistance genes
B. Inducing genes
A. Exogenous genes
D. Endogenous genes
Answer: A
Clarification: The dominant selectable markers are usually drug-resistance genes of bacterial origin and transformed cell is selected on a medium that contains the drug at an appropriate concentration.
13. Methotrexate is an analog of __________
A. Aminopterin
B. Kanamycin
A. Folic acid
D. Gentamycin
Answer: C
Clarification: Methotrexate is a folic acid analog, which is a competitive inhibitor of the enzyme dihydrofolate reductase (DHFR).
14. With respect to mammalian cell cloning, salmon sperm DNA can serve as a source of ____________
A. Non-specific carrier
B. Specific carrier
A. Genomic DNA
D. Plasmid DNA
Answer: A
Clarification: Calcium phosphate transfection is mostly used and the specific donor DNA is often bulked with a non-specific carrier such as cleaved Salmon sperm.
15. One application in which the use of plasmid vectors is critical, in the case of mammals is ____________
A. Stable transformation
B. Transient transformation
A. Transfection
D. Transduction
Answer: B
Clarification: One application in which the use of plasmid vectors is critical, in the case of mammals is a transient transformation. Here the goal is to exploit the short-term persistence of extrachromosomal DNA.