- Which of the following is an example of ex vivo gene therapy?
a) Injection of a virus carrying a normal gene directly into a patient
b) Introduction of engineered cells into the patient’s body after manipulation outside the body
c) Injection of siRNA to silence a gene
d) Use of CRISPR-Cas9 to edit the gene directly inside the patient
Answer: b) Introduction of engineered cells into the patient’s body after manipulation outside the body
Explanation:
Ex vivo gene therapy involves removing cells from a patient, modifying them genetically outside the body, and then reintroducing them into the patient. In contrast, in vivo gene therapy involves delivering the genetic material directly into the patient.
- Which technology was first used for the commercial production of human insulin?
a) CRISPR-Cas9
b) Recombinant DNA technology
c) Somatic gene therapy
d) DNA fingerprinting
Answer: b) Recombinant DNA technology
Explanation:
Recombinant DNA technology was first used to produce human insulin by inserting the insulin gene into bacteria such as Escherichia coli. These genetically modified bacteria produced insulin, which was harvested and purified for medical use.
- Bt toxin is toxic to insects because it:
a) Destroys the insect’s nervous system
b) Inhibits the insect’s protein synthesis
c) Binds to specific receptors in the insect’s gut, causing cell lysis
d) Prevents insect reproduction
Answer: c) Binds to specific receptors in the insect’s gut, causing cell lysis
Explanation:
Bt toxin, produced by Bacillus thuringiensis, binds to receptors in the gut of specific insect larvae. This causes the cells in the gut to lyse, leading to the death of the insect.
- What is the function of DNA ligase in recombinant DNA technology?
a) It cuts DNA at specific sequences.
b) It amplifies DNA fragments.
c) It joins DNA fragments together.
d) It separates DNA fragments by size.
Answer: c) It joins DNA fragments together.
Explanation:
DNA ligase is an enzyme that facilitates the joining of DNA fragments by forming phosphodiester bonds between the ends of the DNA strands. This is essential in creating recombinant DNA molecules.
- Which of the following is used as a marker gene to identify transformed cells in genetic engineering?
a) Insulin gene
b) GFP (Green Fluorescent Protein)
c) Cry gene
d) Myosin gene
Answer: b) GFP (Green Fluorescent Protein)
Explanation:
GFP is commonly used as a marker gene in genetic engineering. Cells expressing GFP can be easily identified due to their fluorescence under UV light, helping to confirm successful transformation.
- Flavr Savr, the first genetically modified tomato, was engineered for:
a) Insect resistance
b) Herbicide tolerance
c) Delayed ripening
d) Improved flavor
Answer: c) Delayed ripening
Explanation:
The Flavr Savr tomato was genetically modified to delay the ripening process, which extended its shelf life. This was achieved by reducing the activity of the enzyme polygalacturonase, which breaks down pectin in the tomato cell walls.
- What is the role of CRISPR-Cas9 in biotechnology?
a) To induce mutations in specific genes
b) To perform genome editing by cutting DNA at specific sites
c) To amplify DNA for sequencing
d) To inhibit RNA synthesis
Answer: b) To perform genome editing by cutting DNA at specific sites
Explanation:
CRISPR-Cas9 is a revolutionary genome-editing tool that allows precise cutting and modification of DNA at specific locations. It has vast applications in genetic research, gene therapy, and biotechnology.
- Which of the following is a common application of RNA interference (RNAi)?
a) Increasing crop yield
b) Silencing specific genes to study their function
c) Promoting genetic diversity in crops
d) Cloning entire organisms
Answer: b) Silencing specific genes to study their function
Explanation:
RNA interference (RNAi) is used to silence or knock down the expression of specific genes, allowing researchers to study gene function and investigate the effects of reducing the levels of specific proteins.
- Which of the following is NOT a step in recombinant DNA technology?
a) Isolation of the desired gene
b) Use of DNA polymerase to cut the DNA
c) Ligation of the DNA into a vector
d) Introduction of the recombinant vector into the host cell
Answer: b) Use of DNA polymerase to cut the DNA
Explanation:
DNA polymerase is not used to cut DNA; instead, restriction enzymes are responsible for cutting DNA at specific sequences. DNA polymerase is used to replicate DNA during the amplification process in PCR.
- Which bacterium is commonly used in the production of transgenic plants?
a) Escherichia coli
b) Agrobacterium tumefaciens
c) Pseudomonas aeruginosa
d) Rhizobium
Answer: b) Agrobacterium tumefaciens
Explanation:
Agrobacterium tumefaciens is widely used in genetic engineering to create transgenic plants. Its Ti plasmid can be modified to deliver desired genes into the plant genome.
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