๐ Topic 01 of 6 ยท Chapter 04 ยท Biotechnology & Genetic Engineering
Biotechnology Basics โ DNA, Genes & Techniques
DNA structure, recombinant DNA, PCR, gel electrophoresis, DNA fingerprinting โ complete notes for UPSC & PSC exams.
๐งฌ DNA โ Structure & Key Facts
- DNA = Deoxyribonucleic Acid = genetic material of most organisms
- Double helix structure discovered by James Watson and Francis Crick (1953) โ Nobel Prize 1962
- DNA is made of nucleotides โ each has a sugar (deoxyribose), phosphate group, and nitrogenous base
- 4 bases: Adenine (A), Thymine (T), Guanine (G), Cytosine (C)
- Base pairing: A-T and G-C (complementary base pairing)
- Human genome = ~3 billion base pairs; ~20,000-25,000 genes
- Gene = segment of DNA that codes for a protein
๐งฌ Key Biotechnology Techniques
| Technique | What it Does | Applications |
|---|---|---|
| Recombinant DNA Technology | Cuts and joins DNA from different organisms using restriction enzymes and ligases | GM crops, insulin production, vaccines, gene therapy |
| PCR (Polymerase Chain Reaction) | Amplifies specific DNA sequences โ makes millions of copies | COVID-19 testing, forensics, paternity testing, disease diagnosis |
| Gel Electrophoresis | Separates DNA fragments by size using electric current | DNA fingerprinting, genetic analysis |
| DNA Fingerprinting | Creates unique DNA profile using VNTRs (variable number tandem repeats) | Forensics, paternity testing, identifying disaster victims |
| Cloning | Creates genetically identical copies of organisms or genes | Dolly the sheep (1996) = first cloned mammal |
| Gene Sequencing | Reads the order of nucleotides in DNA | Human Genome Project; personalised medicine |
๐งฌ Key Discoveries & Nobel Prizes
- DNA double helix โ Watson & Crick (1953) โ Nobel Prize 1962
- PCR โ Kary Mullis (1983) โ Nobel Prize Chemistry 1993
- DNA fingerprinting โ Alec Jeffreys (1984)
- Restriction enzymes โ Werner Arber, Daniel Nathans, Hamilton Smith โ Nobel Prize 1978
- Human Genome Project โ completed 2003 โ sequenced entire human genome
๐ Key Exam Points:
โข DNA double helix = Watson & Crick (1953) = Nobel Prize 1962
โข PCR = Kary Mullis (1983) = amplifies DNA = COVID-19 testing
โข DNA fingerprinting = Alec Jeffreys (1984) = forensics
โข Human Genome Project = completed 2003 = ~3 billion base pairs
โข Recombinant DNA = restriction enzymes + ligases = basis of genetic engineering
โข DNA double helix = Watson & Crick (1953) = Nobel Prize 1962
โข PCR = Kary Mullis (1983) = amplifies DNA = COVID-19 testing
โข DNA fingerprinting = Alec Jeffreys (1984) = forensics
โข Human Genome Project = completed 2003 = ~3 billion base pairs
โข Recombinant DNA = restriction enzymes + ligases = basis of genetic engineering