Multiple Choice Questions on Restriction enzymes
1. Which of the following is the most important discovery that leads to the development of rDNA (recombinant DNA) technology a) discovery of double helix model by Watson and crick b) Discovery of DNA as genetic material c) discovery of restriction enzymes d) all of these
1. c) discovery of restriction enzymes
10. Restriction sites of type II enzymes a) generally are palindromic sequences b) consists of 4-6 bp c) mostly are palindromes with rotational symmetry d) all of these
10.d) all of these
11.Single stranded unpaired extensions formed by restriction enzyme upon cleavage is called as a) blunt ends b) flush ends c) sticky ends d) none of these
11.c) sticky ends
12. Which of the following ions are required for the activity of Type II restriction enzymes a) Ca2+ b) Mg2+ c) Cl2+ d) Mn2
12.b) Mg2+
14. Nathen, Arber and Smith were awarded with Nobel prize for physiology and medicine in the year a) 1970 b) 1974 c) 1978 d) 1980
14. c) 1978
13. Restriction enzymes a) are present in bacteria and are involved in host restriction system b) cleave viral DNA inside bacterium c) are enzymes involved in defence against bacteriophages d) all of these
13. d) all of these
15. The first Type II enzyme isolated was a) Eco R1 b) Hind III c) Bam HI d) Sal I
15. b) Hind III
2. Who discovered restriction enzymes a) Watson and Crick b) Jacob and Monad c) Nathan, Arber and Smith d) Boyer and Cohen
2. c) Nathan, Arber and Smith
3. Restriction enzymes are enzymes a) capable of cutting DNA molecule b) capable of adding nucleotides to the 3'OH end c) capable of restricting protein synthesise d) capable of joining DNA molecules
3. a) capable of cutting DNA molecule
4. Restriction enzymes capable of making internal cuts in a DNA molecule is called a) restriction exonuclease b) restriction endonuclesae c) both a and b d) S1 nuclease
4. b) restriction endonuclesae
5. Restriction enzymes are also called a) molecular knives b) molecular scissors c) molecular scalpels d) all of these
5. d) all of these
6. The sequence recognised by the restriction enzyme to cut the DNA is called a) recognition site b) restriction site c) both a and b d) cleavage sites
6. c) both a and b
7.Which of the following are true regarding restriction enzyme a) restriction enzyme are used to cut DNA molecule b) restriction enzyme are used to construct restriction maps c) restriction enzyme are used in RFLP d) all of these
7. d) all of these
8. The type of restriction enzymes used in rDNA technology is a) Type I b) Type II c) Type III d) all of these
8. b) Type II
9. Which of the following statements are true regarding restriction enzymes a) Type I and II enzymes cuts far away from the restriction sites b) Type II cuts DNA within restriction sites c) Eco R1 is a Type II restriction enzyme d) all of these
9. d) all of these
