Class 12 Biology Chapter 12 Biotechnology and its Applications Notes
12.1 Biotechnological Applications in Agriculture
Biotechnology has helped in developing genetically modified (GM) crops with better yield, pest resistance and nutritional quality.
Bt Toxin and Bt Crops
Why Bt toxin does not kill the bacteria itself
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Bt toxin is produced in inactive (protoxin) form
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It becomes active only inside the alkaline gut of insects
👉 Hence, bacteria are not harmed.
Cry Proteins
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Cry proteins are insecticidal proteins
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Produced by Bacillus thuringiensis
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cry gene encodes this protein
Uses of Cry Protein:
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Development of Bt crops
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Bt cotton → resistant to bollworm
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Bt tobacco → resistant to hornworm
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Advantages and Disadvantages of GM Crops
Advantages:
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Increased crop yield
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Resistance to pests and diseases
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Reduced use of chemical pesticides
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Improved nutritional quality (biofortification)
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Tolerance to abiotic stresses
Disadvantages:
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Possible environmental risks
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Development of resistant pests
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High cost of seeds
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Ethical and biosafety concerns
12.2 Biotechnological Applications in Medicine
Biotechnology plays a major role in diagnosis, prevention and treatment of diseases.
Recombinant Bacteria
Transgenic Bacteria
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Bacteria containing a foreign gene in their genome
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Example:
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Human insulin gene inserted into E. coli
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Produces recombinant insulin for diabetes treatment
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Gene Therapy
Gene therapy is the correction of a genetic defect by introducing a normal gene.
Example: ADA Deficiency
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Caused by deletion of gene for adenosine deaminase
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Leads to immune system failure
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Treated by inserting functional ADA gene into bone marrow cells
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Provides long-term relief
Production of Human Growth Hormone (Concept)
Steps involved:
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Isolation of human growth hormone gene
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Insertion into plasmid vector
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Transformation into E. coli
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Expression of hormone
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Purification and clinical use
Oral Protein Pharmaceuticals
Example:
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Edible vaccines (Hepatitis B, Influenza)
Method:
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Gene for antigen inserted into plant (e.g., potato)
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Transgenic plant produces vaccine protein
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Consumed orally
Major Problem:
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Protein degradation by digestive enzymes
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Low stability in gastrointestinal tract
12.3 Transgenic Animals
Transgenic animals carry foreign genes in their genome.
Uses:
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Study of gene regulation
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Disease models (cancer, Alzheimer’s)
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Production of therapeutic proteins
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Vaccine safety testing
12.4 Ethical Issues in Biotechnology
Ethical issues arise due to:
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Manipulation of genes
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GM food safety
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Animal rights
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Biopiracy
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Environmental risks
Need for Regulation:
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Biosafety guidelines
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Ethical committees
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Government regulations
Golden Rice
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A transgenic rice variety
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Rich in β-carotene (provitamin A)
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Helps prevent vitamin A deficiency
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Developed by Ingo Potrykus and Peter Beyer
Blood and Digestive Enzymes
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Blood does not contain active proteases or nucleases
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If present, they would digest body tissues
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Some enzymes exist only in inactive form
Oil Removal from Seeds (Conceptual)
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Identify genes responsible for oil synthesis
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Remove or silence those genes using rDNA technology
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Regenerate plant with oil-free seeds
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Useful for specific industrial applications
12.5 Summary (Exam Ready ✨)
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Biotechnology improves agriculture and medicine
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Bt crops reduce pesticide use
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Recombinant DNA produces lifesaving drugs
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Gene therapy treats genetic disorders
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Transgenic animals aid research
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Ethical regulation is essential
✍️ Top 10 Short Question–Answers
Q1. What are GM crops?
Answer: Genetically modified crops are plants whose genes are altered using biotechnology.
Q2. Why does Bt toxin not kill the bacteria producing it?
Answer: Because Bt toxin is produced in inactive protoxin form and becomes active only in insect gut.
Q3. What are Cry proteins?
Answer: Insecticidal proteins produced by Bacillus thuringiensis.
Q4. Name one Bt crop and its target pest.
Answer: Bt cotton – bollworm.
Q5. What is a transgenic bacterium?
Answer: A bacterium containing a foreign gene in its genome.
Q6. What is gene therapy?
Answer: Correction of a genetic defect by introducing a normal gene.
Q7. Which disease is treated by ADA gene therapy?
Answer: ADA deficiency.
Q8. What are transgenic animals?
Answer: Animals carrying foreign genes in their genome.
Q9. What is Golden Rice rich in?
Answer: β-carotene (provitamin A).
Q10. Why are biosafety guidelines necessary?
Answer: To regulate ethical, environmental and health risks of biotechnology.
📝 Long Answer Questions
Q1. Explain Bt crops and their advantages.
Answer:
Bt crops are genetically modified plants containing cry genes from Bacillus thuringiensis.
Key points:
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Cry gene produces insecticidal protein
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Bt toxin becomes active in insect gut
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Targets specific pests
Advantages:
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Increased crop yield
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Resistance to insect pests
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Reduced use of chemical pesticides
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Environment-friendly
Q2. Describe biotechnological applications in medicine.
Answer:
Biotechnology helps in treatment and prevention of diseases.
Applications include:
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Recombinant insulin: Produced by E. coli for diabetes
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Gene therapy: Treatment of ADA deficiency
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Human growth hormone: Produced using rDNA technology
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Edible vaccines: Oral vaccines from transgenic plants
Thus, biotechnology produces safe and effective medicines.
Q3. Explain transgenic animals and their uses.
Answer:
Transgenic animals carry foreign genes introduced by biotechnology.
Uses:
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Study of gene regulation
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Disease models (cancer, Alzheimer’s)
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Production of therapeutic proteins
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Vaccine safety testing
They help in medical research and drug development.
📝 PYQs (Previous Year Questions)
🔹 1️⃣ Very Short Answer Questions (1 Mark)
What are genetically modified (GM) crops?
Why does Bt toxin not kill Bacillus thuringiensis?
What are Cry proteins?
Name the bacterium used to produce Bt crops.
Name one Bt crop.
What is a transgenic organism?
What is gene therapy?
Which disease is treated by ADA gene therapy?
What is Golden Rice rich in?
Name one ethical issue related to biotechnology.
🔹 2️⃣ Short Answer Questions (2–3 Marks)
Explain why Bt toxin is harmless to bacteria but lethal to insects.
What are the advantages of GM crops?
What are the disadvantages of GM crops?
What is recombinant insulin? How is it produced?
Explain gene therapy with reference to ADA deficiency.
What are edible vaccines? Mention one limitation.
What are transgenic animals? Write any two uses.
Why is Golden Rice called a biofortified crop?
Why are biosafety guidelines necessary in biotechnology?
Why do blood plasma proteins not digest body tissues?
🔹 3️⃣ Long Answer Questions (3–5 Marks)
Describe biotechnological applications in agriculture.
Explain Bt crops with suitable examples.
Describe applications of biotechnology in medicine.
Explain gene therapy. How is it used to treat ADA deficiency?
Describe transgenic animals and their importance.
Discuss ethical issues related to biotechnology.
Write a detailed note on Golden Rice.
🔹 4️⃣ Difference-Based PYQs (Very Important)
GM crops vs Conventional crops
Protoxin vs Active toxin
Gene therapy vs Conventional therapy
Transgenic animals vs Normal animals
Biofortification vs Chemical supplementation
🔹 5️⃣ Assertion–Reason / Concept-Based PYQs
Bt crops reduce the use of chemical pesticides. Justify.
Gene therapy provides long-term treatment for genetic disorders. Explain.
Edible vaccines are not widely used. Give reason.
Transgenic animals are important in medical research. Justify.
Biotechnology needs strict regulation. Explain.
🔹 6️⃣ Diagram / Flowchart Based PYQs
Diagrammatic representation of Bt cotton mechanism.
Flowchart showing steps in production of recombinant insulin.
Flowchart of gene therapy for ADA deficiency.
❓ FAQs (5)
FAQ 1. Why is Bt toxin insect-specific?
Because it becomes active only in alkaline gut of insects.
FAQ 2. What problem is solved by Golden Rice?
Vitamin A deficiency.
FAQ 3. Why are edible vaccines not very stable?
Due to degradation by digestive enzymes.
FAQ 4. Why are proteases absent in blood?
To prevent digestion of body tissues.
FAQ 5. Why is regulation required in biotechnology?
To address ethical issues, biosafety and environmental risks.
| Chapter No. | Chapter Name | Visit |
|---|---|---|
| 1 | Reproduction in Organisms | Visit |
| 2 | Sexual Reproduction in Flowering Plants | Visit |
| 3 | Human Reproduction | Visit |
| 4 | Reproductive Health | Visit |
| 5 | Principles of Inheritance and Variation | Visit |
| 6 | Molecular Basis of Inheritance | Visit |
| 7 | Evolution | Visit |
| 8 | Human Health and Disease | Visit |
| 9 | Strategies for Enhancement in Food Production | Visit |
| 10 | Microbes in Human Welfare | Visit |
| 11 | Biotechnology: Principles and Processes | Visit |
| 12 | Biotechnology and its Applications | Visit |
| 13 | Organisms and Populations | Visit |
| 14 | Ecosystem | Visit |
| 15 | Biodiversity and Conservation | Visit |
| 16 | Environmental Issues | Visit |
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