This set of Basic Genetic Engineering Questions and Answers focuses on “Cultured Cells in Mammals and Restricted Areas in Intact Organisms-02”.
1. T protein is required for replication. It is a product of:
a) delayed early transcription
b) late transcription
c) early transcription
d) both early and late replication
Explanation: T protein is required for replication and it is a product of early transcription. If T protein is absent, the introduction of DNA takes place only by integration.
2. Vaccinia virus, is a commonly used virus and it is a member of pox virus family. It has a large genome of _____ and can accept at least ____ of foreign DNA.
a) 200kb, 25kb
b) 1000kb, 200kb
c) 500kb, 50kb
d) 800kb, 100kb
Explanation: Vaccinia virus is a commonly used virus. It is having a large genome of size 200kb and can atleast accept foreign DNA of size 25kb.
3. Vaccinia virus produces its own ______ , which is functional in _____ of infected cells where the virus also replicates.
a) DNA polymerase, nucleus
b) DNA polymerase, cytoplasm
c) RNA polymerase, cytoplasm
d) RNA polymerase, nucleus
Explanation: Vaccinia virus produces its own RNA polymerase which is functional in the cytoplasm of infected cells and virus also replicates here.
4. It is beneficial to use retrovirus for genetic manipulation of cells in the culture. Is the given statement true or false?
Explanation: Use of retrovirus is quite beneficial for manipulation of cells in the culture. It is so because they infect the susceptible cells with great efficiency and bring about stable integration.
5. LNSX is a retrovirus and is combined with ______ in order to create a shuttle vector.
a) eukaryotic plasmid
b) prokaryotic plasmid
c) either eukaryotic or prokaryotic plasmid
d) yeast plasmid
Explanation: LNSX is a retrovirus and is combined with a prokaryotic plasmid so that it can act as a shuttle vector. The retrovirus contains neomycin resistance gene as a selectable marker and a promoter.
6. The retroviral transfected DNA is infected into mammalian cells by helper retrovirus. Helper retrovirus should not be packaged and the method adopted for this is?
a) Deletion of the packaging signal in the helper genome
b) Deletion of multiple parts of the helper genome
c) Division of the helper genome into several pieces
d) All the above given methods can be adopted
Explanation: Helper retrovirus is used for introduction of transfected DNA into mammalian cells. But it is necessary that helper retrovirus itself should not be packaged. It can be achieved by deletion of the packaging signal in the helper genome, deletion of multiple parts of the helper genome and division of the helper genome into several pieces.
7. Choose the incorrect statement in respect to MACs.
a) They are mammalian or human artificial chromosomes
b) Large stretches of DNA (in excess of 100 kb) can be inserted
c) A selectable marker is required
d) It can be maintained for long term
Explanation: Nowdays, MACs have been developed and they are the mammalian or human artificial chromosomes. They can carry large stretches of DNA and can be maintained for long term without the requirement of being selected.
8. Centromere is the most important component of the human artificial chromosome. It is constructed from tandemly repeated copies of 171 bp of ______ DNA sequence.
a) alpha satellite
b) beta satellite
c) satellite 2
d) satellite 1
Explanation: Centromere is the most important component of the human artificial chromosome. It is constructed from tandemly repeated copies of 171 bp of alpha satellite DNA sequence. There are other satellite DNA sequences such as beta, satellite 1 and 2.
9. Constitutive promoters are majorly obtained from:
c) mammalian cells
d) viral cells
Explanation: Constitutive promoters are majorly obtained from viral cells. They commonly include, SV40 promoters, adenovirus major late promoter etc. In some cases they are also obtained from mammalian cells.
10. In naturally occurring bacterial systems, tetracycline binding repressor protein, binds in the _____ of tetracycline to the control sequence and _______ transcription.
a) presence, activates
b) absence, activates
c) absence, inactivates
d) presence, inactivates
Explanation: In naturally occurring bacterial systems, tetracycline binding repressor protein binds in the absence of tetracycline to the control sequence tet0 and inactivates transcription.
11. Tetracycline binding repressor protein when fused to transcription activator protein from herpes simple virus, then it is called as transactivator protein (tTA). Is the given statement true or false?
Explanation: Transactivator protein is the protein formed by fusion of tetracycline binding repressor protein to the transcription activator protein from herpes simple virus. The protein which is repressing originally transforms into activating in nature.
12. Expression of tTA gene is ________ by doxycycline which is _______ analogue.
a) activated, tetracycline
b) inactivated, chloramphenicol
c) activated, chloramphenicol
d) inactivated, tetracycline
Explanation: Expression of tTA gene is inactivated by doxycyline which is tetracycline analogue. It is very strong and the expression is very less in the presence of doxycycline.
13. Glucorticoid-responsive element is ______ promoter from ______ of mouse mammory tumour virus (MMTV).
a) inducible, short terminal repeat region
b) inducible, long terminal repeat region
c) constitutive, short terminal repeat region
d) constitutive, long terminal repeat region
Explanation: Glucorticoid-responsive element is an inducible promoter from long terminal repeat region of MMTV. Promoters are basically of two types constitutive and inducible.
14. There are a group of promoters from the genes for metallothioneins. These are a group of proteins rich in ______ residues.
c) either cysteine or methionine
d) cysteine and methionine both
Explanation: These are rich in cytseine residues which chelate heavy metals to reduce their toxicity. The promoter is induced by treatment of cells with heavy metal ions such as zinc and cadmium.
15. The amount of expression of DNA inserted into a vector _______ on promoter and ______ on chromosomal location.
a) depends only on, not depends
b) depends, depends also
c) doesn’t depends, but depends
d) neither depends, nor depends
Explanation: The amount of expression of DNA inserted into a vector is not only dependent on the promoter used but also depends on chromosomal location.
Sanfoundry Global Education & Learning Series – Genetic Engineering.
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