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Biotechnology

Recombinant DNA, PCR, gene cloning, applications

Key Concepts
  • Recombinant DNA technology: cut DNA with restriction enzymes, join with ligase, insert into vector
  • PCR (polymerase chain reaction): amplifies specific DNA sequences exponentially
  • Gel electrophoresis: separates DNA fragments by size (smaller moves further)
  • Transgenic organisms: genetically modified organisms (GMOs) with foreign genes
  • CRISPR-Cas9: precise genome editing tool
Important Formulae
PCR cycles vs copies After n cycles: 2ⁿ copies of target DNA
Quick Tips
  • Restriction enzymes recognise specific palindromic sequences and cut DNA — molecular scissors.
  • Bt toxin (from Bacillus thuringiensis) is used in transgenic Bt cotton and Bt corn to resist insects.
  • Humulin: human insulin produced by recombinant E. coli — first commercial biotech drug.
Sample Practice Questions

  1. Ti plasmid from Agrobacterium tumefaciens is used in:

    • Animal cloning
    • Plant genetic engineering (gene transfer)
    • Bioremediation
    • Antibody production
    Show answer

    Answer: Plant genetic engineering (gene transfer)

  2. ELISA (Enzyme-Linked Immunosorbent Assay) is used to detect:

    • DNA sequences
    • Specific antigens or antibodies
    • Protein structure
    • Enzyme activity only
    Show answer

    Answer: Specific antigens or antibodies

  3. Transgenic animals have:

    • Modified behaviour only
    • Foreign gene stably integrated into their genome
    • Cloned body parts
    • Enhanced natural genes only
    Show answer

    Answer: Foreign gene stably integrated into their genome

  4. Gel electrophoresis separates DNA fragments by:

    • Colour
    • Size (smaller fragments move farther)
    • Charge only
    • Temperature
    Show answer

    Answer: Size (smaller fragments move farther)

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Practice Questions

Practice 20 randomly selected NEET questions on Biotechnology. Answers are revealed after each question.

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