a) enzymes having same recognition sequence and always cutting at the same site
b) enzymes having same recognition sequence and always cutting at different site
c) enzymes having different recognition site and cutting at the same site
d) enzymes having same recognition site and they may or may not cut at the same site
Q.2.
Isocaudomers are defined as the enzymes which recognize different sequence but generate same ends. Which of the following pairs of enzymes can be termed as isocuadomers?
a) DpnI (GA|TC) and Sau3A (|GATC)
b) BamHI (G|GATCC) and Sau3A (|GATC)
c) DpnI (GA|TC) and BglII (A|GATCT)
d) XbaI (T|CTAGA) and BamHI (G|GATCC)
Q.3.
The specificity of an enzyme is affected by the concentration of buffer used. This phenomenon is termed as:
a) star activity
b) specificity elevation
c) concentration gradient effects
d) diamond activity
Q.4.
Which of the following statements is correct with respect to a unit of an enzyme?
a) One unit of enzyme is defined as the amount of enzyme required to digest 1miligram of standard DNA in a specific time of 1hr and under given temperature conditions
b) The amount of enzyme required doesn’t vary with the number of sites present in the DNA
c) If more number of sites is there in the DNA more units of enzyme are required in comparison to same amount of DNA with fewer sites
d) The amount of enzyme required for digestion of DNA with less number of sites is more than that of more number of sites in the same amount of DNA
Q.5.
Which of the following statement is correct regarding partial digestion?
a) It is defined as the conditions where all the sites in the DNA sequence are not recognized
b) The number of fragments created by partial digestion are same as that of complete digestion
c) It is not useful in representation of genomic library
d) Exactly half of the sites in the DNA are recognized
Q.6.
Which of the following is the correct nomenclature of a restriction enzyme obtained from the first activity of strain R of Escherichia coli?
a) EcoR1
b) EscRI
c) EcorI
d) EcoRI
Q.7.
Why is DNase preferred over restriction endonuclease in some cases?
a) DNase is preferred over restriction endonuclease in some cases because the latter are not able to recognize some of the restriction sites
b) DNase is more specific as restriction endonuclease, so the required fragment is obtained
c) DNase is less specific as compared to restriction endonuclease, hence there are more chances of representation of all the possible fragments
d) DNase is abundant in comparison the restriction endonuclease
Q.8.
The ends created by use of DNase have unique single stranded sequences.
a) True
b) False
Q.9.
Besides enzymatic means, physical stress can also be used for cleaving the DNA. Which of the following statements is true?
a) Sonication, needles, syringes, etc all come under the category of physical stress
b) In physical stress, there are no chances of contamination
c) The ends obtained have unique sequences
d) They are less effective than DNase treatment
Q.10.
Phosphatases refer to __________
a) the enzymes which add phosphate group at the end of the DNA molecule in the place of hydroxyl group
b) the enzymes which hydrolytically remove phosphate group from the DNA molecules and replace them with hydroxyl group
c) the enzymes responsible for removal of phosphate group from the DNA molecules and replace them with hydrogen
d) the enzymes responsible for replacing hydrogen in the DNA molecules with the phosphate group
Q.11.
How is phosphatase related to the ligation reactions?
a) Phosphate group is not required for the ligation reaction to take place, thus phosphatase is helpful
b) It is helpful in ceasing the unwanted ligation
c) Phosphatases are not at all related to ligation reactions
d) They act as a catalyst in case of the ligation reaction
Q.12.
How can phosphatase activity terminated prior to a ligation reaction?
a) By heating
b) By cooling
c) By creating vibrations
d) By alternatively cooling and heating
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