Biotechnology — Set 3

Correct Answer: D. Agrobacterium tumefaciens

• **Agrobacterium tumefaciens** = Agrobacterium tumefaciens is often called 'nature’s smallest genetic engineer' due to its ability to transfer DNA. • **Key significance** — It naturally infects plants and integrates its plasmid DNA into the plant genome. • 💡 Wrong-option analysis: A: Escherichia coli is a different concept; B: Thermus aquaticus is a different concept; C: Bacillus subtilis is a different concept.

Correct Answer: A. Marine and aquatic applications

• **Marine and aquatic applications** = Blue biotechnology involves using marine biological resources to develop new products. • **Key significance** — This includes extracting medicinal compounds from sponges or using algae for biofuel production. • 💡 Wrong-option analysis: B: Atmospheric research is a different concept; C: Space biology is a different concept; D: Deep-sea mining is a different concept.

Correct Answer: D. Complementary DNA synthesized from mRNA

• **Complementary DNA synthesized from mRNA** = Complementary DNA (cDNA) is synthesized from a messenger RNA template using the enzyme reverse transcriptase. • **Key significance** — It contains only the coding sequences (exons) of a gene, making it ideal for cloning in bacteria. • 💡 Wrong-option analysis: A: Circular DNA is a different concept; B: Cytoplasmic DNA is a different concept; C: Chloroplast DNA is a different concept.

Correct Answer: C. Thermus aquaticus

• **Thermus aquaticus** = Taq polymerase is extracted from the bacterium Thermus aquaticus, which lives in hot springs. • **Key significance** — Because it is heat-stable, it does not denature during the high-temperature cycles of PCR. • 💡 Wrong-option analysis: A: E. coli is a different concept; B: Yeast is a different concept; D: Human cells is a different concept.

Correct Answer: D. RT-PCR

• **RT-PCR** = Reverse Transcription Polymerase Chain Reaction (RT-PCR) converts viral RNA into DNA and then amplifies it. • **Key significance** — It is considered the 'gold standard' for detecting the presence of the virus with high sensitivity. • 💡 Wrong-option analysis: A: Rapid Antigen Test is a different concept; B: MRI is a different concept; C: Blood Sugar Test is a different concept.

Correct Answer: C. Directly injecting DNA into plant cells

• **Directly injecting DNA into plant cells** = A gene gun shoots microscopic gold or tungsten particles coated with DNA into target cells. • **Key significance** — It is a physical method of transformation used when biological vectors like Agrobacterium are not effective. • 💡 Wrong-option analysis: A: Killing pests is a different concept; B: Sequencing proteins is a different concept; D: Sterilizing lab equipment is a different concept.

Correct Answer: D. Targeted therapy for diseases like cancer

• **Targeted therapy for diseases like cancer** = Monoclonal antibodies are identical immune system proteins designed to bind to specific targets, such as cancer cells. • **Key significance** — They can flag cells for destruction or block specific receptors to stop disease progression. • 💡 Wrong-option analysis: A: Pain relief is a different concept; B: Muscle growth is a different concept; C: Nutritional supplements is a different concept.

Correct Answer: D. Bioinformatics

• **Bioinformatics** = Bioinformatics combines biology, computer science, and statistics to analyze large genomic and proteomic datasets. • **Key significance** — It is essential for mapping the human genome and predicting protein structures. • 💡 Wrong-option analysis: A: Biophysics is a different concept; B: Biochemistry is a different concept; C: Biometry is a different concept.

Correct Answer: D. Replace or fix faulty genes to treat genetic disorders

• **Replace or fix faulty genes to treat genetic disorders** = Gene therapy involves inserting a functional gene into a patient's cells to correct a genetic defect. • **Key significance** — It targets the root cause of hereditary diseases rather than just treating the symptoms. • 💡 Wrong-option analysis: A: Change eye color is a different concept; B: Clone extinct animals is a different concept; C: Speed up evolution is a different concept.

Correct Answer: A. Polyhydroxyalkanoates (PHAs)

• **Polyhydroxyalkanoates (PHAs)** = PHAs are biodegradable polyesters produced by bacteria as energy storage molecules. • **Key significance** — They can be harvested and processed into plastics that break down naturally in the environment. • 💡 Wrong-option analysis: B: Polystyrene is a different concept; C: PVC is a different concept; D: Polythene is a different concept.