Biotechnology Applications: PCR, Cloning, Recombinant DNA - Higher Difficulty Problems
Q. In recombinant DNA technology, what is the role of restriction enzymes?
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A.
To amplify DNA
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B.
To cut DNA at specific sequences
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C.
To ligate DNA fragments
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D.
To transcribe RNA
Solution
Restriction enzymes cut DNA at specific sequences, allowing for the insertion of DNA fragments into vectors.
Correct Answer: B — To cut DNA at specific sequences
Q. In the context of gene expression, what is the function of a promoter?
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A.
To enhance mRNA stability
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B.
To initiate transcription
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C.
To terminate transcription
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D.
To splice introns
Solution
A promoter is a DNA sequence that initiates transcription by providing a binding site for RNA polymerase.
Correct Answer: B — To initiate transcription
Q. What is the primary purpose of the polymerase chain reaction (PCR)?
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A.
To amplify a specific DNA segment
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B.
To sequence DNA
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C.
To clone DNA fragments
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D.
To analyze gene expression
Solution
PCR is primarily used to amplify a specific DNA segment, making millions of copies for further analysis.
Correct Answer: A — To amplify a specific DNA segment
Q. What is the purpose of gel electrophoresis in molecular biology?
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A.
To amplify DNA
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B.
To separate DNA fragments by size
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C.
To clone DNA
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D.
To synthesize RNA
Solution
Gel electrophoresis separates DNA fragments based on size, allowing for analysis and visualization.
Correct Answer: B — To separate DNA fragments by size
Q. What is the role of a vector in recombinant DNA technology?
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A.
To amplify RNA
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B.
To carry foreign DNA into a host cell
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C.
To cut DNA at specific sites
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D.
To synthesize proteins
Solution
A vector is a DNA molecule used to carry foreign DNA into a host cell for replication and expression.
Correct Answer: B — To carry foreign DNA into a host cell
Q. What is the significance of the 'sticky ends' produced by some restriction enzymes?
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A.
They allow for easier ligation of DNA fragments
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B.
They prevent DNA degradation
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C.
They enhance PCR efficiency
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D.
They facilitate RNA transcription
Solution
'Sticky ends' created by certain restriction enzymes allow for easier ligation of DNA fragments by providing complementary overhangs.
Correct Answer: A — They allow for easier ligation of DNA fragments
Q. What type of mutation results in a premature stop codon?
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A.
Missense mutation
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B.
Nonsense mutation
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C.
Silent mutation
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D.
Frameshift mutation
Solution
A nonsense mutation introduces a premature stop codon, leading to truncated proteins.
Correct Answer: B — Nonsense mutation
Q. Which enzyme is essential for synthesizing new DNA strands during PCR?
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A.
DNA ligase
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B.
Taq polymerase
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C.
Reverse transcriptase
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D.
Restriction enzyme
Solution
Taq polymerase is a heat-stable enzyme that synthesizes new DNA strands during the PCR process.
Correct Answer: B — Taq polymerase
Q. Which technique is used to introduce foreign DNA into a host cell?
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A.
PCR
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B.
Transformation
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C.
Gel electrophoresis
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D.
Cloning
Solution
Transformation is the process of introducing foreign DNA into a host cell, often used in cloning.
Correct Answer: B — Transformation
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