Engineering Questions with Answers - Multiple Choice Questions

MCQs on Enzymes for DNA Manipulation

1 - Question

An enzyme which synthesis, DNA from RNA is called___________
a) DNA polymerase
b) RNA polymerase
c) Nucleases
d) Reverse transcriptase

View Answer

Answer: d
Explanation: Reverse transcriptase was discovered by Howard Temin at the University of Wisconsin, also known as RNA directed DNA polymerase which synthesis DNA from RNA.




2 - Question

Kornberg enzyme has both 3’-5’ and 5’-3’ exonuclease activity.
a) True
b) False

View Answer

Answer: a
Explanation: Kornberg enzyme is DNA polymerase I, which have exclusively both 3’ -5’ and 5’-3’ exonuclease activity. It also has 5’-3’ polymerase activity.




3 - Question

Name the bacterium from which Taq DNA polymerase derived?
a) Thermus aquaticus
b) Salmonella
c) Cyanobacteria
d) E.coli

View Answer

Answer: a
Explanation: Taq polymerase derived from thermostable bacteria called thermus aquaticus.it is basically used in PCR and have the ability to withstand with 90°C temperature.




4 - Question

Name the enzyme which degrades DNA molecule by breaking its phosphodiester bonds?
a) DNA polymerase
b) Nucleases
c) Ligase
d) Reverse transcriptase

View Answer

Answer: b
Explanation: Nucleases are the enzymes which break phosphodiester bonds of DNA that link one nucleotide to another. Nucleases are of two types i.e., endonucleases and exonucleases.




5 - Question

Which of the following is NOT an endonuclease?
a) Mung bean nuclease
b) S1 nuclease
c) Terminal deoxynucleotidal transferase
d) RNase A

View Answer

Answer: c
Explanation: Endonuclease are those which break internal phosphodiester bonds of DNA while exonuclease removes nucleotide from the end of the DNA. Examples: mung bean nuclease, S1 nuclease, Rnase A, and RNase H.




6 - Question

Which of the following endonuclease has been purified from Aspergillus oryzae?
a) S1 nuclease
b) RNase H
c) RNase A
d) Mung bean nuclease

View Answer

Answer: a
Explanation: S1 nuclease has been derived from Aspergillus oryaze and used to degrade single strand RNA and DNA but does not affect ds DNA or DNA-RNA hybrid.




7 - Question

Name the enzyme which degrade dsDNA after recognizing specific nucleotide sequences?
a) RNase H
b) Restriction endonuclease
c) DNA polymerase
d) Ligases

View Answer

Answer: b
Explanation: Restriction endonuclease is also called restriction enzymes and works on the specific nucleotide sequence called restriction site. These enzymes restrict the entry of foreign DNA into bacteria.




8 - Question

Which of the following is NOT the property of restriction enzymes?
a) Recognizes palindromic sequences
b) Two fold axial symmetry
c) Recognize specific site according to DNA sources
d) Cut down randomly

View Answer

Answer: c
Explanation: Restriction enzyme recognizes specific restriction sites which are independent of DNA sources.




9 - Question

Which of the following type of restriction enzyme does not require ATP for cleavage?
a) Type I
b) Type II
c) Type III
d) Type IV

View Answer

Answer: b
Explanation: On the basis of properties restriction enzymes has been divided into type I, type II, and type III. Type I and Type III require ATP and magnesium while Type II requires only magnesium.




10 - Question

. Name the restriction enzyme which recognizes different sequences, but produces same ends?
a) DAM methylase
b) Isoschizomers
c) Neoschizomers
d) Isocaudomers

View Answer

Answer: d
Explanation: Isocaudomers recognizes different sequences but produces same ends while Isoschizomers recognizes the same sequences and cut in the same pattern.




11 - Question

Which enzyme join DNA molecules together?
a) Polymerase
b) Nucleases
c) Ligases
d) Linkers

View Answer

Answer: c
Explanation: DNA ligases are used to join DNA molecules together by synthesizing phosphodiester bond between the nucleotides.

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