Part 5: rDNA Technology Process (25 MCQs)
Part 5: rDNA Technology Process – Isolation, Cutting, Joining, Insertion (25 MCQs)
Q101. The first step in recombinant DNA technology is:
a) Ligation
b) Isolation of genetic material (DNA)
c) Transformation
d) Selection
Answer: b
- b) Correct: DNA isolation is the first step before manipulation.
Q102. DNA can be isolated from cells by disrupting:
a) Cell wall and membrane
b) Ribosomes
c) Mitochondria only
d) Proteins only
Answer: a
- a) Correct: Lysis of cell wall & membrane releases DNA.
Q103. In plant cells, DNA isolation requires breaking:
a) Cellulose cell wall
b) Chitin cell wall
c) Peptidoglycan wall
d) None
Answer: a
- a) Correct: Cellulose wall of plants must be broken for DNA release.
Q104. In bacteria, the cell wall is degraded by:
a) Lysozyme
b) Cellulase
c) Chitinase
d) Pectinase
Answer: a
- a) Correct: Lysozyme digests bacterial peptidoglycan.
Q105. Chitinase is used for isolating DNA from:
a) Plants
b) Fungi
c) Bacteria
d) Animals
Answer: b
- b) Correct: Chitinase breaks fungal cell walls.
Q106. After cell lysis, proteins and RNA are removed by:
a) DNase and protease
b) RNase and protease
c) Lysozyme only
d) Cellulase
Answer: b
- b) Correct: RNase removes RNA; protease removes proteins.
Q107. Purified DNA can be precipitated by adding:
a) Acetone
b) Ethanol
c) Water
d) Hydrochloric acid
Answer: b
- b) Correct: DNA precipitates with chilled ethanol.
Q108. Restriction endonucleases cut DNA to produce:
a) Replication
b) Fragments with sticky/blunt ends
c) New plasmids
d) mRNA
Answer: b
- b) Correct: Restriction enzymes generate sticky/blunt DNA fragments.
Q109. In agarose gel electrophoresis, DNA fragments move towards:
a) Cathode (-)
b) Anode (+)
c) Randomly
d) Do not move
Answer: b
- b) Correct: DNA is negatively charged → migrates towards positive electrode (anode).
Q110. Agarose gel electrophoresis separates DNA based on:
a) Shape
b) Size/length of fragments
c) Charge only
d) Protein content
Answer: b
- b) Correct: Smaller fragments migrate faster in gel → size separation.
Q111. Ethidium bromide is used in gel electrophoresis because it:
a) Cuts DNA
b) Binds DNA and fluoresces under UV light
c) Digests proteins
d) Lyses cells
Answer: b
- b) Correct: EtBr intercalates in DNA and fluoresces → visualization.
Q112. Ligation in rDNA technology refers to:
a) Breaking DNA
b) Joining DNA fragments with DNA ligase
c) Separating DNA
d) Inserting DNA into host
Answer: b
- b) Correct: DNA ligase joins foreign DNA fragment with vector DNA.
Q113. The enzyme used to ligate DNA fragments is:
a) Restriction enzyme
b) DNA ligase
c) Taq polymerase
d) Helicase
Answer: b
- b) Correct: DNA ligase seals phosphodiester bonds between DNA pieces.
Q114. Joining foreign DNA with plasmid creates:
a) Recombinant DNA molecule
b) Viral DNA
c) RNA transcript
d) Antibiotics
Answer: a
- a) Correct: Vector + foreign DNA = recombinant DNA.
Q115. Transformation is the process of:
a) Replication of plasmid
b) Introduction of recombinant DNA into host cell
c) Cutting DNA with RE
d) Protein synthesis
Answer: b
- b) Correct: Transformation introduces recombinant DNA into host.
Q116. Which method is commonly used to confirm DNA fragments after digestion?
a) Microscopy
b) Gel electrophoresis
c) PCR
d) Hybridization
Answer: b
- b) Correct: Electrophoresis separates & confirms DNA fragments.
Q117. The foreign DNA is introduced into host by means of:
a) Vector
b) PCR
c) Antibody
d) Protein
Answer: a
- a) Correct: Vectors carry foreign DNA into host cells.
Q118. After transformation, selection of recombinants is done using:
a) Antibiotic resistance
b) Blue-white screening
c) Reporter genes
d) All of the above
Answer: d
- d) Correct: All are used for selecting recombinants.
Q119. DNA fragments are purified from agarose gel by:
a) Centrifugation
b) Elution
c) Electroporation
d) Blotting
Answer: b
- b) Correct: Elution extracts DNA from gel for cloning.
Q120. Which step ensures DNA fragment is integrated into plasmid?
a) Transformation
b) Ligation
c) Screening
d) Electrophoresis
Answer: b
- b) Correct: Ligation → integration of DNA fragment into plasmid.
Q121. The recombinant plasmid after ligation is introduced into host by:
a) Transformation
b) Electrophoresis
c) Protein injection
d) RNA transcription
Answer: a
- a) Correct: Transformation introduces recombinant plasmid into host.
Q122. Insertional inactivation is used to distinguish:
a) Transformed vs. non-transformed cells
b) Recombinants vs. non-recombinants
c) Host vs. vector
d) RNA vs. DNA
Answer: b
- b) Correct: Insertional inactivation identifies recombinant plasmids.
Q123. Which chemical is used for precipitation of DNA during purification?
a) Ethanol
b) Methanol
c) Chloroform
d) NaCl
Answer: a
- a) Correct: Ethanol precipitation isolates pure DNA.
Q124. Which of the following is NOT part of rDNA process?
a) DNA isolation
b) Ligation
c) Electrophoresis
d) Photosynthesis
Answer: d
- d) Correct: Photosynthesis is unrelated.
Q125. Which is the final step in recombinant DNA technology?
a) Isolation of DNA
b) Transformation into host
c) Expression of foreign gene and product recovery
d) Electrophoresis
Answer: c
- c) Correct: Goal = gene expression + product recovery (downstream processing).
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