UPSC CSE Prelims
Recombinant DNA Technology Previous Year Questions (PYQs)

Detailed Explanation:

Answer: Option 1 — Functional chromosomes can be created by joining segments of DNA taken from cells of different species.

This statement is incorrect because creating fully functional chromosomes by simply joining DNA segments from different species is not currently feasible. Chromosomes are highly complex structures requiring species-specific regulatory elements, centromeres, telomeres, and structural proteins that cannot be arbitrarily combined from different organisms to create functional units.

✅ Statement 1 – Incorrect: While synthetic chromosomes and chimeric DNA constructs exist, functional chromosomes cannot be simply created by joining segments from different species due to complex species-specific regulatory requirements.
✅ Statement 2 – Correct: Synthetic biology enables the chemical synthesis of artificial functional DNA sequences in laboratories, including synthetic genes and even entire viral genomes.
✅ Statement 3 – Correct: Polymerase Chain Reaction (PCR) is a standard technique that amplifies DNA segments outside living cells in vitro.
✅ Statement 4 – Correct: Cell culture and tissue culture techniques routinely enable plant and animal cells to divide and grow in laboratory petri dishes using nutrient media.

📝 Short Notes: DNA Technology & Genetic Engineering

• Synthetic DNA: Artificial DNA sequences can be chemically synthesized in laboratories for various applications including gene therapy and research.
• PCR (Polymerase Chain Reaction): A revolutionary technique developed by Kary Mullis that amplifies specific DNA segments millions of times outside living cells.
• Cell Culture: Technique of growing cells in controlled artificial conditions outside their natural environment, fundamental to biotechnology and medical research.
• Chromosomes: Complex structures consisting of DNA wrapped around histone proteins, containing centromeres, telomeres, and species-specific regulatory elements.
• Chimeric DNA: DNA constructs containing sequences from different sources, commonly used in genetic engineering, but different from functional chromosomes.
• Synthetic Biology: The field has achieved milestones like creating synthetic bacterial genomes (Mycoplasma mycoides, 2010) but functional multi-species chromosomes remain beyond current capability.