Chapter 12 — Biotechnology and Its Applications — covers applications in agriculture (Bt crops, Golden Rice), medicine (gene therapy, insulin), and related ethical/biosafety issues. Carries 5-7 marks.
Key Concepts
Applications in Agriculture
Bt Crops
Bt toxin gene from Bacillus thuringiensis is transferred to crop plants
Gene produces Cry protein (crystalline protein) → toxic to specific insect larvae
Cry protein is inactive in bacteria → becomes active in insect gut (alkaline pH) → creates pores in gut → insect dies
Cry1Ac, Cry2Ab: Bt cotton (against cotton bollworm)
Cry1Ab: Bt corn (against corn borer)
Gene produces Cry protein (crystalline protein) → toxic to specific insect larvae
Cry protein is inactive in bacteria → becomes active in insect gut (alkaline pH) → creates pores in gut → insect dies
Cry1Ac, Cry2Ab: Bt cotton (against cotton bollworm)
Cry1Ab: Bt corn (against corn borer)
RNA Interference (RNAi)
dsRNA (double-stranded RNA) silences a specific mRNA → gene is switched off
Used to create nematode-resistant tobacco: host produces specific dsRNA → nematode ingests it → nematode’s mRNA silenced → parasite cannot survive
Used to create nematode-resistant tobacco: host produces specific dsRNA → nematode ingests it → nematode’s mRNA silenced → parasite cannot survive
Golden Rice
Rice biofortified with β-carotene (provitamin A) by introducing genes from daffodil and bacteria. Addresses Vitamin A deficiency.
Applications in Medicine
Genetically Engineered Insulin
Humulin: Human insulin produced in E. coli
Eli Lilly (1983) — first commercially produced rDNA product
Human insulin has 2 chains: A (21 aa) and B (30 aa) linked by disulphide bonds
Proinsulin → C-peptide removed → active insulin
Eli Lilly (1983) — first commercially produced rDNA product
Human insulin has 2 chains: A (21 aa) and B (30 aa) linked by disulphide bonds
Proinsulin → C-peptide removed → active insulin
Gene Therapy
First successful: ADA deficiency (Adenosine Deaminase — needed for immune function)
Lymphocytes collected from patient → functional ADA gene inserted using retrovirus vector → cells returned to patient
Not permanent cure — needs repeated treatment unless bone marrow cells are treated
Lymphocytes collected from patient → functional ADA gene inserted using retrovirus vector → cells returned to patient
Not permanent cure — needs repeated treatment unless bone marrow cells are treated
Molecular Diagnostics
- PCR: Amplify pathogen DNA for detection (HIV, TB, etc.)
- ELISA: Antigen-antibody interaction → detect infection
- DNA probes: Hybridise with specific pathogen DNA
Transgenic Animals
- Rosie: First transgenic cow — produced human α-lactalbumin-enriched milk
- Uses: study gene regulation, test drug safety, produce biological products
Ethical Issues — Biopiracy
- Biopiracy: Unauthorised use of bioresources/traditional knowledge by corporations
- Examples: Neem (W.R. Grace), Turmeric (wound healing patent — revoked), Basmati rice (RiceTec patent)
- GEAC (Genetic Engineering Approval Committee): Indian regulatory body for GMO trials and release
Quick Revision Points
- Bt crops: Cry protein (from B. thuringiensis) → kills insect larvae; Bt cotton uses Cry1Ac/Cry2Ab
- RNAi: dsRNA silences specific gene → nematode-resistant tobacco
- Humulin: human insulin from E. coli (Eli Lilly, 1983)
- Gene therapy: ADA deficiency — first example; lymphocytes + ADA gene via retrovirus
- Rosie: first transgenic cow (human α-lactalbumin in milk)
- Golden Rice: β-carotene enriched
- Biopiracy: neem, turmeric, basmati cases
- GEAC: regulatory body for GMOs in India
Chapter Navigation
Previous: Biotechnology Principles and Processes Class 12 Notes
Next: Organisms and Populations Class 12 Notes
Related Chapters in Class 12 Biology
- Biotechnology Principles and Processes Class 12 Notes
- Microbes in Human Welfare Class 12 Notes
- Human Health and Disease Class 12 Notes
Practice What You Learned
Test yourself with our NEET Mock Test Set 1 to see how well you’ve mastered the concepts.