The document discusses recombinant DNA technology, including key discoveries like restriction enzymes that allow DNA from different sources to be cut and spliced together. Restriction enzymes cut DNA at specific recognition sequences, sometimes leaving overhangs of unpaired nucleotides called sticky ends that allow precise joining of DNA fragments. Ligases are used to join DNA molecules by forming phosphodiester bonds between the 3' OH of one fragment and the 5' phosphate of another. Polymerases help synthesize new DNA strands. Methylases protect host DNA from restriction enzymes. Recombinant DNA techniques have many applications in research and biotechnology.

1. RECOMBINANT DNA TECHNOLOGY
1.Which of the following is the most important discovery that leads to the development of rDNA
technology?
(a)Discovery pf double helix model by Watson and Crick
(b)Discovery of DNA as genetic material
(c)Discovery ofrestriction enzymes
(d)All of these
2.Restriction enzymes capable of making internal cuts in a DNA molecule is called
(a)Restriction Endonuclease
(b)Restriction Exonuclease
(c)Both (a) and (b)
(d)S1 nuclease
3.Single stranded unpaired extensions formed by Restriction Enzyme upon cleavage is called
(a)Blunt ends
(b)Flush ends
(c)Sticky ends
(d)None of these
4.Which of the following enzyme is used to synthesize DNA using an mRNA template?
(a)Taq polymerase
(b)Alkaline phosphatase
(c)Reverse transcriptase
(d)Nuclease
5.Which of the following enzyme is used to join two DNA molecule?
(a)Nuclease
(b)Restriction enzymes
(c)Lyases

2. (d)Ligases
6.The enzyme that adds mononucleotide triphosphates to the 3’ OH group of a DNA fragment is
(a)Polynucleotide kinase
(b)Terminal nucleotidyl transferase
(c)Terminal Phosphoryl transferase
(d)All of these
7.Klenow enzyme is the product of enzyme breakdown of
(a)DNA Polymerase I
(b)DNA Polymerase II
(c)DNA Polymerase III
(d)RNA Polymerase
8.Selective degradation of single stranded DNA is carried out by the enzyme
(a)Nuclease
(b)Ribonuclease
(c)SI nuclease
(d)Deoxyribonuclease
9.Which of the following is a Thermo stable DNA polymerase?
(a)Taq polymerase
(b)Vent polymerase
(c)Pfu polymerase
(d)All of these
10.Eco R1 is a
(a)Endonuclease
(b)Polymerase enzyme
(c)Ligase
(d)Exonuclease

3. 11.Which of the following statements is correct with respect to T4 DNA ligase?
(a)It can carry out only blunt ended ligations
(b)It doesn’t require ATP
(c)It requires a phosphate group at 3’ end and a hydroxyl group at 5’ end for the molecule to be joined
(d)It is obtained from T4 bacteriophage upon infection by E.coli
12.Type II cuts the sequence in the following way as
(a)Within the recognition sequence
(b)At 100-1000 nucleotides away from the recognition sequence
(c) At 27-30nucleotides away from the recognition sequence
(d)It cuts randomly
13.Which enzyme used to remove phosphate group from the 5’ end of the DNA?
(a)Restriction enzymes
(b)Alkaline phosphatase
(c)Polynucleotide kinase
(d)Ribonuclease H
14.Which polymerase can be used in conjunction with appropriate phage promoters in order to have
high levels of specific transcription?
(a)RNA dependent DNA polymerase
(b)DNA dependent RNA polymerase
(c)RNA dependent RNA polymerase
(d)DNA dependent DNA polymerase
15.Which of the following enzyme protect a DNA strand from cleavage restriction enzymes of the
host bacterium?
(a)Restriction Endonuclease
(b)Restriction Exonuclease
(c)Methyl transferase

4. (d)Polynucleotide kinase
16.The co-factor required for the T4 DNA ligase enzyme is
(a)ATP
(b)GTP
(c)NAD+
(d)FAD+
17.The enzyme used in homopolymer tailing in recombinant DNA technology is
(a)Terminal deoxy nucleotidyl transferase
(b)Terminal DNA polymerase
(c)Terminal dT synthase
(d)Terminal nucleotide synthase
18. What is the particular nucleotide sequence of a double-helical segment called?
(a) Overhang
(b) Restriction enzymes
(c) Restriction fragment
(d) Recognition sequence
19. Zinc-finger nucleases is
(a)Naturalrestriction enzyme
(b)Type of polymerase enzyme
(c)Artificial restriction enzyme
(d)Type of helicase enzyme
20.Blunt ends created by the restriction endonuclease can be joined.
(a)True
(b)False