Complete Summary and Solutions for Biotechnology and Its Applications – NCERT Class XII Biology, Chapter 10 – Agricultural Biotechnology, Medical Biotechnology, Transgenic Animals, Ethical Issues
Comprehensive summary and explanation of Chapter 10 'Biotechnology and Its Applications' from the NCERT Class XII Biology textbook, covering biotechnological applications in agriculture including genetically modified crops, tissue culture, biopesticides, medical biotechnology for producing human insulin, gene therapy, molecular diagnosis, transgenic animals and related ethical considerations, with detailed answers to all textbook exercises.
Biotechnology and Its Applications - Class 12 NCERT Chapter 10 - Ultimate Study Guide, Notes, Questions, Quiz 2025
Biotechnology and Its Applications
Chapter 10: Biology - Ultimate Study Guide | NCERT Class 12 Notes, Questions, Examples & Quiz 2025
Full Chapter Summary & Detailed Notes - Biotechnology and Its Applications Class 12 NCERT
Overview & Key Concepts
Chapter Goal: Explore biotechnological tools for improving agriculture, medicine, and industry; focus on GMOs, recombinant therapeutics, gene therapy, transgenic animals, and ethical concerns. Exam Focus: Principles (e.g., Bt toxin mechanism, RNAi process), applications (e.g., golden rice, insulin production), diagrams (e.g., pro-insulin maturation, dsRNA protection). 2025 Updates: Emphasis on sustainable biotech (e.g., climate-resilient crops), CRISPR ethics ties. Fun Fact: Bt cotton reduced pesticide use by 50% in India. Core Idea: Biotech harnesses living systems for human benefit while addressing biosafety. Real-World: mRNA vaccines (COVID) build on gene therapy concepts. Ties: Links to Ch 11 (tools) and Ch 12 (principles). Expanded: All subtopics (10.1-10.4) covered point-wise with principles, steps, biotech relevance, pros/cons for visual/conceptual learning.
Wider Scope: From plant tissue culture to ethical biopiracy; role in food security, healthcare equity, and biodiversity conservation.
Expanded Content: Detailed mechanisms (e.g., Bt protoxin activation), case studies (e.g., Basmati patent), global impacts.
Fig. 10.1: Cotton boll (Description)
Labelled diagram: (a) Destroyed boll with bollworms visible; (b) Fully mature undamaged boll. Visual: Side-by-side comparison showing pest damage vs. healthy GM crop.
10.1 Biotechnological Applications in Agriculture
Options for Food Production Increase: (i) Agro-chemical based (fertilizers/pesticides - expensive, environmental harm); (ii) Organic (sustainable but low yield); (iii) Genetically engineered crops (precise, efficient).
Green Revolution Limitations: Tripled supply but insufficient for population; relies on agrochemicals unaffordable for developing farmers; conventional breeding too slow.
Tissue Culture & Totipotency: Regenerate whole plants from explants (any cell/part) in sterile nutrient media (sucrose, salts, vitamins, auxins/cytokinins). Discovered 1950s; enables rapid propagation.
Micropropagation: Produces thousands of genetically identical somaclones (e.g., tomato, banana, apple) commercially; visit lab for hands-on.
Protoplast Fusion & Somatic Hybridization: Fuse naked protoplasts (wall-digested cells) from desirable varieties; grow into hybrids (e.g., pomato - tomato + potato, but not commercially viable due to undesired traits).
Genetically Modified Organisms (GMOs): Genes altered for traits; benefits: (i) Abiotic stress tolerance (cold/drought/salt/heat); (ii) Pest resistance (reduced pesticides); (iii) Lower post-harvest losses; (iv) Efficient mineral use (soil conservation); (v) Enhanced nutrition (e.g., golden rice - Vitamin A enriched).
Additional GMO Uses: Tailor-made plants for starches, biofuels, pharmaceuticals.
Pest-Resistant Plants: Bt Toxin: From Bacillus thuringiensis (Bt); cry genes cloned into plants (e.g., Bt cotton - cryIAc for bollworms; Bt corn - cryIAb for borers). Mechanism: Protoxin crystals inactive in bacteria; insect gut alkaline pH activates, binds midgut cells, forms pores, causes lysis/death. Insect-specific, safe for non-targets.
Nematode Resistance: RNAi: Silences mRNA via dsRNA (cellular defense against viruses/transposons). Strategy: Introduce nematode genes via Agrobacterium into host; produces sense/antisense RNA → dsRNA → mRNA degradation; parasite cannot survive (e.g., tobacco vs. Meloidogyne incognita).
(a) Roots of control plant heavily infested; (b) Transgenic roots protected 5 days post-infection. Visual: Side-by-side root images showing galls in control vs. clean transgenic roots.
10.2 Biotechnological Applications in Medicine
Recombinant Therapeutics Impact: Mass production of safe drugs; no immune responses (unlike animal-derived); 30 approved globally, 12 in India.
10.2.1 Genetically Engineered Insulin: For adult-onset diabetes; animal insulin causes allergies. Human insulin: Two chains (A/B) linked by disulfides; synthesized as pro-insulin (with C-peptide, removed for maturation). Production: Eli Lilly (1983) - Separate A/B DNA in E. coli plasmids; extract, combine via disulfides. Cannot be oral (digested by proteases).
Diagram: Pro-Insulin Maturation: Pro-insulin → remove C-peptide → insulin (A + B chains).
10.2.2 Gene Therapy: Corrects defective genes by inserting normal ones (e.g., via retroviral vectors). First case (1990): 4-year-old with ADA deficiency (immune disorder from gene deletion). Steps: Culture patient's lymphocytes, insert ADA cDNA, reinfuse (periodic, not permanent); embryonic insertion for cure. Bone marrow transplant/enzyme replacement alternatives but not fully curative.
10.2.3 Molecular Diagnosis: Early detection vital; conventional methods (serum/urine) too late. Techniques: rDNA, PCR (amplifies low pathogen DNA/RNA, e.g., HIV mutations, genetic disorders); probes (radioactive ssDNA/RNA hybridize to target, autoradiography detects mutations); ELISA (antigen-antibody interaction for pathogen/antibody detection).
Fig. 10.3: Maturation of pro-insulin into insulin (simplified) (Description)
Pro-insulin structure: A and B chains linked by disulfides, with C-peptide loop; arrow shows cleavage to mature insulin (A + B) + free C-peptide.
(i) Normal Physiology/Development: Study gene regulation/effects (e.g., insulin-like growth factor via introduced genes).
(ii) Disease Study: Models for human diseases (e.g., cancer, cystic fibrosis, rheumatoid arthritis, Alzheimer’s) to test treatments.
(iii) Biological Products: Produce medicines (e.g., Rosie cow milk with human alpha-lactalbumin - 2.4g/L, better for babies; α-1-antitrypsin for emphysema; attempts for PKU/cystic fibrosis).
(iv) Vaccine Safety: Test vaccines (e.g., transgenic mice for polio safety, potential monkey replacement).
(v) Chemical Safety Testing: Toxicity in sensitive models (faster results than non-transgenic).
10.4 Ethical Issues
Regulation Need: Manipulations require ethical standards to evaluate harm/help to organisms/ecosystems; unpredictable GM effects on environment.
GEAC Role: Genetic Engineering Approval Committee assesses GM research validity/safety for public release.
Patent Problems: Grants for GM uses create issues; public anger over companies patenting indigenous resources (e.g., 1997 US patent on Basmati rice-derived variety, restricting Indian sales; attempts on turmeric/neem).
Biopiracy: Unauthorized use of bio-resources/traditional knowledge by MNCs without compensation; industrialized nations exploit developing countries' biodiversity/knowledge. Solutions: Laws for benefit-sharing (e.g., Indian Patents Bill amendment for emergencies/R&D).
Summary
Biotech yields useful products via microbes/plants/animals; tissue culture/somatic hybridization for plant varieties; rDNA for GMOs with novel traits (yield/stress tolerance/nutrition/pest resistance).
Point-wise depth, diagrams described, real cases (Bt India impact); free 2025 with mnemonics, ethics debates for retention.
Key Themes & Tips
Aspects: Catalyst optimization, downstream processing, biosafety vs. innovation.
Tip: Memorize cry genes, RNAi steps; draw mechanisms for diagrams.
Exam Case Studies
Bt cotton yield boost; ADA therapy ethics.
Project & Group Ideas
Model pomato fusion demo.
Debate: GMOs vs. organic farming.
Research: Golden rice in malnutrition.
Key Definitions & Terms - Complete Glossary
All terms from chapter; detailed with examples, relevance. Expanded: 40+ terms grouped by subtopic; added advanced like protoxin, dsRNA for depth/easy flashcards.
Totipotency
Capacity of cell/explant to regenerate whole plant. Ex: Leaf cell → plantlet. Relevance: Basis of tissue culture.
Micropropagation
Rapid clonal plant production via tissue culture. Ex: Banana somaclones. Relevance: Commercial scaling.
Virus for gene delivery. Ex: ADA cDNA insertion. Relevance: Stable integration.
Autoradiography
Detection of radioactive probes. Ex: Mutation screening. Relevance: Hybridization visualization.
Tip: Group by section; examples for recall. Depth: Mechanisms tie to genetics. Errors: Confuse cry genes. Historical: Green Revolution. Interlinks: Ch 11 tools. Advanced: CRISPR in ethics. Real-Life: Bt in India. Graphs: Yield curves. Coherent: Agriculture → Medicine → Ethics. For easy learning: Flashcard per term with example/app.
60+ Questions & Answers - NCERT Based (Class 12) - From Exercises & Variations
Based on chapter + expansions. Part A: 10 (1 mark, one line), Part B: 10 (4 marks, five lines), Part C: 10 (6 marks, eight lines). Answers point-wise in black text. Easy: Structured for marks.
Part A: 1 Mark Questions (10 Qs - Short)
1. What is totipotency in the context of plant tissue culture?
1 Mark Answer: The capacity of a plant cell or explant to regenerate a whole plant.
2. Name the process of producing genetically identical plants through tissue culture.
1 Mark Answer: Micropropagation.
3. What is a somaclone?
1 Mark Answer: A genetically identical plant produced from somatic cells via tissue culture.
4. Give an example of a somatic hybrid plant.
1 Mark Answer: Pomato (tomato + potato).
5. What is the primary benefit of GM crops like golden rice?
1 Mark Answer: Enhanced nutritional value (e.g., Vitamin A enrichment).
6. Name the bacterium that produces Bt toxin.
1 Mark Answer: Bacillus thuringiensis.
7. What activates Bt protoxin in the insect gut?
1 Mark Answer: Alkaline pH solubilizing crystals.
8. What is RNAi used for in GM plants?
1 Mark Answer: Silencing nematode-specific mRNA for resistance.
9. What is the first clinical gene therapy example?
1 Mark Answer: ADA deficiency in a 4-year-old girl (1990).
10. What does GEAC stand for?
1 Mark Answer: Genetic Engineering Approval Committee.
Part B: 4 Marks Questions (10 Qs - Medium, Exactly 5 Lines Each)
1. Explain the process of micropropagation and its major advantage.
4 Marks Answer:
Micropropagation involves culturing explants in nutrient media with growth regulators to produce thousands of plants rapidly.
Steps: Select explant, sterilize, inoculate in MS medium, subculture, root/harden, acclimatize.
Produces somaclones - genetically identical to parent.
Major advantage: High multiplication rate in short time, uniform quality for commercial crops like banana.
Also enables virus-free plants from meristems.
2. Describe somatic hybridization with an example.
4 Marks Answer:
Somatic hybridization fuses protoplasts (wall-less cells) from two plants to create hybrids.
Steps: Isolate protoplasts enzymatically, fuse with PEG/electrofusion, culture to callus, regenerate plant.
Example: Pomato from tomato + potato protoplasts, combining tubers and fruits.
Advantage: Bypasses sexual incompatibility for distant hybrids.
Limitation: Often unstable or lacks desired traits commercially.
3. List five benefits of GM crops.
4 Marks Answer:
Made crops tolerant to abiotic stresses like cold, drought, salt, heat.
Reduced reliance on chemical pesticides via pest-resistant crops (e.g., Bt).
Helped reduce post-harvest losses through delayed ripening.
Increased efficiency of mineral usage by plants, preventing soil exhaustion.
Enhanced nutritional value of food, e.g., golden rice with Vitamin A.
4. Explain the mechanism of Bt toxin action.
4 Marks Answer:
Bt produces protoxin crystals inactive in bacteria but toxic to specific insects.
Insect ingests crystals; alkaline gut pH solubilizes and activates protoxin.
Activated toxin binds midgut epithelial receptors, forms pores.
Pores cause cell swelling, lysis, and insect death.
Specific to lepidopterans/coleopterans/dipterans; safe for humans/non-targets.
5. How does RNAi provide nematode resistance in plants?
4 Marks Answer:
RNAi silences specific mRNA via complementary dsRNA binding, preventing translation.
Nematode genes introduced via Agrobacterium produce sense/antisense RNA in host.
RNAs form dsRNA, trigger Dicer processing to siRNA.
siRNA guides RISC to degrade target nematode mRNA.
Parasite cannot survive in transgenic host (e.g., tobacco vs. M. incognita).
6. Outline the production of human insulin using rDNA technology.
4 Marks Answer:
Human pro-insulin gene (A + B chains + C-peptide) challenging; separate A/B sequences used.
Insert A/B DNA into E. coli plasmids for separate chain production.
Extract chains, combine via disulfide bonds to form mature insulin.
Eli Lilly (1983) pioneered; identical to natural, no allergies.
Advantages: Mass production, safe, no animal sourcing.
7. Describe gene therapy for ADA deficiency.
4 Marks Answer:
ADA deficiency causes SCID due to gene deletion; impairs immune function.
Steps: Culture patient lymphocytes, insert functional ADA cDNA via retrovirus.
Reinfuse modified cells; periodic as lymphocytes mortal.
Alternatives: Bone marrow transplant or enzyme injection, but not curative.
Embryonic insertion for permanent cure; first trial 1990 on 4-year-old.
8. How does PCR aid in molecular diagnosis?
4 Marks Answer:
PCR amplifies trace pathogen DNA/RNA before symptoms appear.
Other: Neem (antifungal patent), turmeric (wound healing).
Response: Indian laws, WTO TRIPS flexibilities.
Global: Nagoya Protocol for access/benefit-sharing.
Ethics: Protect indigenous rights in biotech.
Tip: Diagrams for mechanisms; practice steps. Additional 30 Qs: Variations on ethics, golden rice.
Key Concepts - In-Depth Exploration
Core ideas with examples, pitfalls, interlinks. Expanded: All 10.1-10.4 with steps/examples/pitfalls for easy learning. Depth: Mechanisms, calcs (e.g., yield increase).
Tissue Culture & Micropropagation
Steps: 1. Explant sterilization, 2. MS medium inoculation, 3. Callus/shoot induction, 4. Rooting, 5. Acclimatization. Ex: Virus-free sugarcane (10x yield). Pitfall: Contamination. Interlink: Totipotency to GM. Depth: Auxin:cytokinin ratio for organogenesis.
Somatic Hybridization
Steps: 1. Protoplast isolation, 2. Fusion, 3. Culture to hybrid plant. Ex: Pomato (sterile). Pitfall: Chromosome instability. Interlink: Protoplasts to electroporation. Depth: PEG vs. electrofusion efficiency.
GM Crops Benefits
Steps: Gene isolation, vector, transformation, selection. Ex: Golden rice (psy + crtI genes, 23x Vit A). Pitfall: Allergenicity. Interlink: RNAi stacking. Depth: 20% global crop GM.
