This set of Life Sciences Multiple Choice Questions & Answers (MCQs) focuses on “Vectors”.
1. Circular DNA used for cloning is called___________
a) DNA polymerase
b) RNA polymerase
Explanation: Plasmid is the circular bacterial DNA, which carries genes which are useful but not essential for survival. These are said to be extrachromosomal DNA.
2. Without origin of replication, DNA cannot be replicated in the cell.
Explanation: Origin of replication is the segment of DNA that is recognized by the replication enzymes. Absence of replication origin leads to the failure of replication.
3. Which of the following is NOT a cloning vector?
a) Bacterial plasmid
Explanation: Cloning vectors are DNA molecules that are used to transport sequences between the host and the donor. Most of the vectors are genetically engineered.
4. Cloning vector has the following properties, except one?
a) Contain genetic marker for selection
b) Ability to replicate
c) Multiple restriction site for entry of DNA
d) Contain nonessential DNA to optimize cloning
Explanation: Cloning vector has a single and unique restriction site for the entry of DNA and facilitate cloning. Cloning vector is used to amplify single molecule of DNA into multiple copies.
5. Which of the following is NOT the characteristics of the plasmid?
a) Replicate independently in a host cell
b) Selectable marker gene
c) Contain single cloning site
d) Small in size
Explanation: These vectors are used to clone DNA that varies in size from several base pairs to several thousand base pairs. It contains multiple cloning sites.
6. Which of the following is TRUE for YAC?
a) Recognizes palindromic sequences
b) Two fold axial symmetry
c) Recognize specific site according to DNA sources
d) Derived from DNA of the Yeast
Explanation: YAC stands for Yeast Artificial Chromosome that is derived from the DNA of the yeast and is ligated to bacterial plasmid by genetic engineering.
7. Which of the following is NOT an example of Lambda phages?
Explanation: M13 is an example of philamentous phages while the rest is Lambda phages. Lambda phages are double stranded DNA phages that replicate in E.coli, follows either lysogenic or lytic mode.
8. Name the vector system used for plant transformation?
c) M13 phage
d) Resistance plasmid
Explanation: Agrobacterium tumefaciens is a powerful vector system for plant transformation. It is used to transfer genes from bacteria to plant in the form of T-DNA.
9. Name the first vector used for a mammalian cell?
a) Lambda phage
Explanation: SV40 is a small virus cloning vector that infects monkey (simian). Mammalian cell was first cloned using SV40 vector.
10. Which of the following cloning vector is used for insect and having a DNA genome?
Explanation: Viral DNA in insect vector is rare, but baculoviruses have been used as a cloning vector for many insects and having dsDNA genome.
Sanfoundry Global Education & Learning Series – Life Sciences.
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