- Which of the following enzymes is used in the PCR (Polymerase Chain Reaction) technique?
a) RNA polymerase
b) DNA ligase
c) Taq polymerase
d) Reverse transcriptase
Answer: c) Taq polymerase
Explanation:
Taq polymerase, derived from the bacterium Thermus aquaticus, is a heat-stable DNA polymerase used in PCR to amplify DNA sequences through repeated cycles of heating and cooling.
- Which of the following is a disadvantage of using genetically modified organisms (GMOs) in agriculture?
a) Increased crop yield
b) Resistance to pests
c) Potential cross-breeding with wild species
d) Reduced pesticide use
Answer: c) Potential cross-breeding with wild species
Explanation:
One concern with GMOs is the possibility of gene flow, where the genetically modified genes might spread to wild relatives, potentially causing ecological imbalances or the development of “superweeds.”
- Golden rice has been genetically engineered to combat:
a) Vitamin A deficiency
b) Vitamin D deficiency
c) Iron deficiency anemia
d) Calcium deficiency
Answer: a) Vitamin A deficiency
Explanation:
Golden Rice is a genetically modified variety of rice that has been engineered to produce beta-carotene, a precursor of Vitamin A, aimed at reducing Vitamin A deficiency, particularly in developing countries.
- Which technique is used to amplify small quantities of DNA for further analysis?
a) Southern blotting
b) Polymerase Chain Reaction (PCR)
c) Northern blotting
d) DNA sequencing
Answer: b) Polymerase Chain Reaction (PCR)
Explanation:
PCR is a molecular biology technique used to amplify small quantities of DNA, making it possible to generate millions of copies of a specific DNA sequence for further analysis.
- Which of the following techniques is used to introduce foreign DNA into bacterial cells?
a) Gel electrophoresis
b) Microinjection
c) Transformation
d) Blotting
Answer: c) Transformation
Explanation:
Transformation is the process by which foreign DNA is introduced into bacterial cells, usually by making the bacterial cells competent to take up DNA, often using heat shock or electroporation.
- Which of the following is an example of a transgenic organism?
a) A sheep that produces human insulin
b) A bacterium that decomposes oil spills
c) A plant with increased drought tolerance
d) A bacterium that fixes nitrogen
Answer: a) A sheep that produces human insulin
Explanation:
A transgenic organism is one that has been genetically modified to carry genes from another species. In this case, a sheep that produces human insulin is an example of a transgenic organism.
- Which of the following is used as a selectable marker in the process of genetic engineering?
a) Antibiotic resistance gene
b) Hemoglobin gene
c) Chlorophyll gene
d) Insulin gene
Answer: a) Antibiotic resistance gene
Explanation:
Selectable markers, like antibiotic resistance genes, are used to identify cells that have successfully incorporated the foreign gene during genetic engineering. Cells that contain the marker gene survive when grown in the presence of the corresponding antibiotic.
- Which of the following methods is used to detect specific sequences of DNA?
a) Western blotting
b) Northern blotting
c) Southern blotting
d) Eastern blotting
Answer: c) Southern blotting
Explanation:
Southern blotting is a technique used to detect specific DNA sequences within a DNA sample by transferring the DNA onto a membrane and probing it with a labeled DNA probe that hybridizes with the target sequence.
- Gene therapy is most suitable for treating diseases caused by:
a) Viruses
b) Bacteria
c) Mutations in single genes
d) Nutritional deficiencies
Answer: c) Mutations in single genes
Explanation:
Gene therapy is primarily used to treat genetic disorders caused by mutations in single genes, such as cystic fibrosis or sickle cell anemia, by delivering functional copies of the defective gene to the patient’s cells.
- Which of the following is a key component of the CRISPR-Cas9 system?
a) Reverse transcriptase
b) Guide RNA
c) Taq polymerase
d) DNA ligase
Answer: b) Guide RNA
Explanation:
In the CRISPR-Cas9 system, guide RNA (gRNA) directs the Cas9 enzyme to the specific DNA sequence that is to be cut, allowing for precise genome editing.
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