CBSE Class 12 Biology – Chapter 12 Biotechnology and Its Applications | Long Answer Type Questions (NCERT Based)

Course, Unit & Examination Details

• Course: CBSE Class XII Biology
• Board: Central Board of Secondary Education
• Unit: IV – Biotechnology
• Chapter: 12 – Biotechnology and Its Applications
• Prescribed By: National Council of Educational Research and Training (NCERT)
• Question Type: Long Answer (5 Marks)
• Answer Length: 120–150 words
• Exam Relevance: CBSE Class 12 Board Examination

CBSE Class 12 Biology Chapter 12 – Biotechnology and Its Applications | 25 Long Answer Questions (NCERT)

SECTION A: Biotechnology in Agriculture (Q1–Q6)

Q1. Explain the role of biotechnology in agriculture.

Ans:
Biotechnology plays a significant role in agriculture by improving crop yield, quality, and resistance to biotic and abiotic stresses. Using recombinant DNA technology, specific genes are introduced into crop plants to develop desirable traits such as pest resistance, herbicide tolerance, and drought tolerance. This reduces dependence on chemical fertilizers and pesticides, lowering environmental pollution. Biotechnology also enables biofortification, which enhances the nutritional value of crops by increasing vitamin, mineral, or protein content. Genetically modified crops help in sustainable agriculture by minimizing crop losses and ensuring food security. Thus, biotechnology supports increased productivity while maintaining ecological balance.

Q2. What are genetically modified crops? State their advantages.

Ans:
Genetically modified crops are plants whose genetic material has been altered using genetic engineering to introduce specific beneficial traits. These traits may include pest resistance, improved nutritional quality, or tolerance to environmental stresses. One major advantage of GM crops is reduced reliance on chemical pesticides, as plants can produce insecticidal proteins themselves. They also provide higher yield and better quality produce. GM crops may have improved shelf life, reducing post-harvest losses. Additionally, biofortified GM crops help combat nutrient deficiencies. Overall, genetically modified crops contribute to sustainable agriculture and enhanced food security.

Q3. Explain biofortification and its importance.

Ans:
Biofortification is the process of increasing the nutritional value of crops using biotechnology. It involves enhancing the content of essential nutrients such as vitamins, minerals, proteins, or fats in food crops. This is achieved by introducing genes that regulate nutrient synthesis or accumulation. Biofortified crops help address malnutrition and micronutrient deficiencies, especially in developing countries. For example, increasing iron or vitamin content in staple crops improves public health without changing dietary habits. Biofortification is a cost-effective and sustainable approach to improving nutrition and reducing health problems related to nutrient deficiency.

Q4. How does biotechnology help reduce pesticide use?

Ans:
Biotechnology reduces pesticide use by developing genetically modified crops that are resistant to insect pests. Such crops contain genes derived from Bacillus thuringiensis that produce insecticidal proteins toxic to specific pests. These plants kill target insects internally, eliminating the need for repeated external pesticide application. This minimizes environmental pollution and reduces harm to beneficial organisms. Farmers benefit from lower production costs and improved yield. Thus, biotechnology promotes eco-friendly pest control and sustainable farming practices.

Q5. Describe the significance of GM crops in sustainable agriculture.

Ans:
GM crops play an important role in sustainable agriculture by increasing productivity while minimizing environmental damage. They reduce the use of chemical pesticides and fertilizers, preserving soil fertility and water quality. Pest-resistant and stress-tolerant crops lower crop losses and ensure stable yields. GM crops also support biofortification, improving nutritional quality. By combining economic benefits with environmental protection, GM crops help meet food demands of a growing population sustainably.

Q6. Mention the limitations and concerns related to agricultural biotechnology.

Ans:
Despite its benefits, agricultural biotechnology raises certain concerns. There is a risk of gene flow from GM crops to wild relatives, potentially affecting biodiversity. Non-target organisms may also be harmed. Long-term ecological effects are not fully understood. Ethical issues related to ownership of genetic resources and dependence of farmers on biotech companies are also significant. Therefore, strict biosafety testing and regulatory measures are essential before commercial release of GM crops.

SECTION B: Bt Crops and RNA Interference (Q7–Q12)

Q7. Explain the mechanism of action of Bt toxin in insects.

Ans:
Bt toxin is produced by Bacillus thuringiensis as an inactive protoxin. In Bt crops, genes encoding this toxin are introduced into plant cells. When an insect feeds on the plant, the protoxin enters its gut. Due to the alkaline pH of the insect gut, the protoxin becomes active. The activated toxin binds to receptors on gut epithelial cells, forming pores that cause cell lysis and death of the insect. This mechanism is specific to target pests and does not affect humans or other non-target organisms.

Q8. Why are Bt crops considered safe for humans?

Ans:
Bt crops are considered safe for humans because the Bt toxin remains inactive in acidic conditions like the human stomach. Activation of the toxin occurs only in the alkaline gut of insects. Moreover, Bt proteins are specific to insect gut receptors, which are absent in humans. Extensive biosafety testing ensures that Bt crops are non-toxic and safe for consumption. Thus, Bt crops provide effective pest control without health risks.

Q9. What is RNA interference? Explain its application in plants.

Ans:
RNA interference (RNAi) is a natural cellular mechanism that silences specific genes by degrading their mRNA. It involves the introduction of double-stranded RNA, which is processed into small interfering RNAs that bind to complementary mRNA and prevent translation. In plants, RNAi is used to develop resistance against pests like nematodes. By silencing essential genes in the pest, RNAi protects crops without affecting the plant or other organisms.

Q10. Compare Bt technology and RNA interference.

Ans:
Bt technology involves introducing genes that produce insecticidal proteins, directly killing pests. RNA interference works by silencing specific genes in pests, preventing their growth or survival. Bt toxins act physically on insect gut cells, while RNAi blocks gene expression. Both methods reduce pesticide use and are environmentally friendly, but RNAi is more specific at the molecular level.

Q11. State the advantages of RNA interference technology.

Ans:
RNAi technology offers high specificity, targeting only selected genes. It avoids harm to non-target organisms and reduces chemical pesticide use. RNAi-based crops are environmentally safe and effective against pests like nematodes. It also minimizes resistance development in pests.

Q12. Name one Bt crop and its target pest.

Ans:
Bt cotton is a genetically modified crop that targets bollworm insects, reducing crop damage and pesticide use.

SECTION C: Biotechnology in Medicine & Gene Therapy (Q13–Q19)

Q13. Describe the production of human insulin using biotechnology.

Ans:
Human insulin is produced using recombinant DNA technology. The insulin gene is isolated and inserted into a bacterial plasmid, which is then introduced into E. coli. The bacteria produce insulin chains that are purified and assembled to form functional insulin. Recombinant insulin is identical to human insulin, highly pure, and does not cause allergic reactions associated with animal-derived insulin. It allows large-scale production at lower cost.

Q14. Explain the medical importance of interferons.

Ans:
Interferons are proteins produced by host cells in response to viral infections. Using recombinant DNA technology, interferons are produced commercially and used to treat viral diseases and certain cancers. They enhance immune response and inhibit viral replication. Their biotechnological production ensures purity and availability for therapeutic use.

Q15. What is gene therapy? Explain ADA deficiency treatment.

Ans:
Gene therapy is a technique used to correct genetic disorders by introducing functional genes into a patient’s cells. In ADA deficiency, a functional ADA gene is inserted into patient lymphocytes using a vector. These cells are reintroduced into the body, restoring immune function. This therapy improves patient health but may require repeated treatment.

Q16. Differentiate between somatic and germline gene therapy.

Ans:
Somatic gene therapy targets body cells and does not affect future generations. Germline gene therapy targets reproductive cells and is heritable. Due to ethical concerns, germline therapy is not practiced.

Q17. State the limitations of gene therapy.

Ans:
Gene therapy is expensive, technically complex, and may show temporary effects. Immune reactions and ethical concerns also limit its application.

Q18. How has biotechnology improved disease diagnosis?

Ans:
Biotechnology enables early and accurate diagnosis using molecular techniques that detect genetic or pathogenic markers, improving treatment outcomes.

Q19. Name two therapeutic proteins produced using biotechnology.

Ans:
Human insulin and human growth hormone are therapeutic proteins produced using biotechnology.

SECTION D: Transgenic Animals & Ethical Issues (Q20–Q25)

Q20. What are transgenic animals? State their uses.

Ans:
Transgenic animals carry foreign genes introduced through genetic engineering. They are used for studying gene regulation, modeling human diseases, testing vaccines, and producing therapeutic proteins.

Q21. Explain pharming with an example.

Ans:
Pharming is the production of pharmaceutical products using transgenic animals. For example, sheep producing human proteins in milk.

Q22. How are transgenic animals useful in vaccine testing?

Ans:
They help test vaccine safety and effectiveness before human trials.

Q23. What is biopatenting? Discuss its concerns.

Ans:
Biopatenting involves granting patents for biological products. It raises concerns about access, equity, and exploitation of natural resources.

Q24. Define biopiracy with an example.

Ans:
Biopiracy is the unauthorized use of biological resources without compensating native communities.

Q25. Why are ethical regulations essential in biotechnology?

Ans:
Ethical regulations ensure safe, responsible, and equitable use of biotechnology while protecting biodiversity and public interest.