Restriction endonuclease or restriction enzymes or molecular scissors are proteins produced by bacteria which cleaves the DNA at particular sites along the molecule. The restriction enzymes in a bacterial enzyme cleaves foreign DNA and hence, destructs infecting entities. These enzymes can be isolated from cells of bacteria and utilized in labs to influence DNA fragments, namely those which encompasses genes. This is why they are the vital tools of recombinant DNA technology.
1. For cloning, restriction enzymes with sticky ends are used for
(a) ease of transformation
(b) easy insertion into plasmids of DNA segments from different sources
(c) easy identification of plasmids with antibiotic resistance
(d) easy identification of plasmids having inserts
Answer: (b)
2. The host controlled restriction is a process associated with
(a) gene of interest
(b) bacteria
(c) plasmid
(d) viruses
Answer: (b)
3. How many bases does the sequence which identifies the restriction enzymes contain?
(a) 1
(b) 4
(c) 6
(d) 12
Answer: (c)
4. The restriction enzymes bind to and cut the sequences of DNA which usually are
(a) antiparallel
(b) not symmetrical about the midpoint
(c) symmetrical about the midpoint
(d) random sequences
Answer: (c)
5. In bacteria, the restriction phenomena occurs naturally as
(a) bacteria produces enzyme
(b) for survival
(c) for efficient cloning
(d) destruction of DNA of the bacterium
Answer: (a)
6. Restriction enzymes are isolated from
(a) Virus
(b) Fungi
(c) Protozoa
(d) Bacteria
Answer: (d)
7. Joining and cutting DNA are these techniques
(a) DNA synthesis
(b) DNA degradation
(c) DNA manipulation
(d) DNA replication
Answer: (c)
8. For the production of a DNA copy, the enzyme which uses RNA is called
(a) DNA polymerase
(b) RNA polymerase
(c) DNA ligase
(d) reverse transcriptase
Answer: (b)
9. This was the first restriction endonuclease that was discovered
(a) BamHI
(b) EcoRI
(c) HindIII
(d) HindII
Answer: (d)
10. This is not a cloning factor
(a) pUC19
(b) SV40
(c) EST
(d) M13
Answer: (c)
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