Genetic Engineering Problems focuses on “Cultured Cells And Bacillovirus”.
1. Autographa californica nuclear polyhedrois virus (AcNPV) is commonly used bacilovirus for infecting cultured cells. The virus is ________ and _______
a) single stranded, linear
b) double stranded, linear
c) double stranded, circular
d) single stranded, circular
Answer: c
Explanation: AcNPV is a commonly used bacilovirus for infecting cultured cells. It is double stranded and circular. It is isolated from caterpillar and infects around 30 species.
2. DNA replication of the AcNPV takes 6 hours after infection. After how many hours of infection new virus particles are produced by budding?
a) 8 hrs
b) 10 hrs
c) 12 hrs
d) 16 hrs
Answer: b
Explanation: After 10 hrs of infection, new virus particles are produced. And these virus particles are termed as extracellular virus particles.
3. The virus particles are held together by polyhedron and p10 protein.
a) True
b) False
Answer: a
Explanation: The virus particles are held together by polyhedron and p10 proteins. Polyhedron protein is of 29kDa. The virus particles are held together as occlusion bodies.
4. The polyhedrin and p10 protein are produced in ____________ amount and other genes are expressed in _________ amount.
a) low, high
b) high, high
c) high, low
d) low, low
Answer: c
Explanation: The polyhedron and p10 protein are expressed in large amounts and other genes are expressed in low amount. The former proteins are up to 20% of protein synthesis.
5. Expression of proteins using nuclear polyhedrosis viruses is advantageous because it gives _______ protein yields and post-translational modifications are _________
a) high, not possible
b) high, possible
c) low, possible
d) low, not possible
Answer: b
Explanation: Expression of proteins using nuclear polyhedrosis viruses is advantageous because it gives high protein yields and post-translational modifications are also possible. These modifications are not possible in prokaryotic systems and yeast or are carried out very less.
6. The size of the viral genome is large and thus poses a problem. This problem can be resolved by using ____________
a) transfer vector
b) co-integration plasmid
c) hybrid vector
d) fusion vector
Answer: a
Explanation: The size of the viral genome is a problem because it is very large. It is solved by using a transfer vector. Transfer vector is composed of sequences that allow propagation of E.coli, the viral promoter, the polyhedrin mRNA polyadenylation signal and the polyhedron gene is flanked by the viral sequences.
7. The gene of interest is inserted into transfer vector and then further into viral genome leading to the formation of modified virus. How can plaques from modified virus differentiated from plaques from wild-type virus?
a) Chemically
b) Visually
c) On the basis of magnetic properties
d) On the basis of longeitivity of plaques
Answer: b
Explanation: Plaques from the recombinant virus and from the wild type virus can be differentiated simply visually.
8. If the DNA is linearized, what is the effect on the recombination frequency?
a) The recombination frequency decreases
b) The recombination frequency increases
c) The recombination may increase or decrease depending on the amount of DNA
d) There is no effect on the recombination frequency
Answer: b
Explanation: If the DNA is linearixed, the recombination frequency increases. It is so because eit makes the DNA more recombinogenic.
9. The recombinant virus can be propagated in E.coli and this is referred to as bacmid.
a) True
b) False
Answer: a
Explanation: The recombinant virus can be propagated in E.coli and this is called as bacmid. This arrangement can be used as shuttle vector.
10. For the generation of recombinant baculovirus, recombinants can be selected by ____________
a) blue-white screening
b) antibiotic resistance
c) either antibiotic resistance or blue white screening
d) radioactivity
Answer: a
Explanation: For the generation of recombinant baculovirus, recombinants can be selected by blue-white screening. After this, the recombinant baculovirus is introduced into insect cells for expression.
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