CBSE Class 12 Biology – Chapter 12 Biotechnology and Its Applications | Case-Based Questions with Answers (NCERT)

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: Case-Based / Source-Based
• Exam Relevance: CBSE Class 12 Board Examination

CBSE Class 12 Biology Chapter 12 – Biotechnology and Its Applications | 25 Case-Based Questions (NCERT)

SECTION A: Biotechnology in Agriculture (Cases 1–5)

Case 1

A farmer adopts genetically modified crops to reduce pesticide use and improve yield. After cultivation, pest damage decreases significantly.

Q. Which biotechnological approach explains this outcome?
Ans: The farmer used pest-resistant genetically modified crops that produce insecticidal proteins, reducing pest attack and minimizing the need for chemical pesticides.

Case 2

A research institute develops crops with enhanced vitamin and mineral content to combat malnutrition.

Q. Identify this biotechnological strategy and its significance.
Ans: This strategy is biofortification. It improves nutritional quality of crops and helps address micronutrient deficiencies in human populations.

Case 3

Farmers notice reduced soil and water pollution after switching to genetically modified crops.

Q. Why does biotechnology contribute to environmental protection?
Ans: Biotechnology reduces chemical fertilizer and pesticide use, lowering environmental pollution and promoting sustainable agriculture.

Case 4

A crop variety survives drought conditions better after genetic modification.

Q. Which type of stress tolerance is involved?
Ans: Abiotic stress tolerance, specifically drought tolerance, achieved by introducing stress-resistant genes into crops.

Case 5

A GM crop shows delayed spoilage during storage.

Q. How does biotechnology help reduce post-harvest losses?
Ans: Genetic modification improves shelf life and resistance to spoilage organisms, reducing post-harvest losses.

SECTION B: Genetically Modified Organisms (GMOs) (Cases 6–10)

Case 6

Scientists introduce a foreign gene into a plant to express a new trait.

Q. What is such an organism called?
Ans: It is called a genetically modified organism (GMO).

Case 7

Concerns arise about transfer of GM genes to wild plant relatives.

Q. Name this phenomenon.
Ans: Gene flow.

Case 8

Before commercial release, GM crops undergo strict testing.

Q. Why is biosafety testing essential?
Ans: Biosafety testing ensures GM crops are safe for humans and the environment.

Case 9

GM crops reduce dependence on chemical pesticides.

Q. State one advantage of this reduction.
Ans: It minimizes environmental pollution and protects beneficial organisms.

Case 10

A GM food crop is approved after regulatory review.

Q. What ensures its safe use?
Ans: Regulatory authorities and biosafety committees ensure safety and compliance.

SECTION C: Bt Crops (Cases 11–15)

Case 11

Bt cotton plants resist bollworm infestation.

Q. Which gene provides this resistance?
Ans: Cry gene from Bacillus thuringiensis.

Case 12

An insect dies after feeding on a Bt crop due to gut cell damage.

Q. Explain the mechanism involved.
Ans: Bt protoxin becomes active in the insect’s alkaline gut, binds to epithelial cells, causes pore formation, and leads to insect death.

Case 13

Humans consume Bt crops without harmful effects.

Q. Why is Bt toxin harmless to humans?
Ans: Bt toxin remains inactive in the acidic human stomach and lacks suitable receptors.

Case 14

Farmers report fewer pesticide sprays after adopting Bt crops.

Q. State one environmental benefit of Bt crops.
Ans: Reduced chemical pesticide usage and lower environmental pollution.

Case 15

Bt crops target specific insects only.

Q. Why is specificity important?
Ans: It prevents harm to non-target organisms and maintains ecological balance.

SECTION D: RNA Interference (RNAi) (Cases 16–18)

Case 16

A plant resists nematode infestation after gene silencing.

Q. Which technique is responsible?
Ans: RNA interference (RNAi).

Case 17

Double-stranded RNA blocks protein production in a pest.

Q. How does RNAi work?
Ans: It degrades specific mRNA, preventing translation and protein synthesis.

Case 18

RNAi affects only the target organism.

Q. Why is RNAi highly specific?
Ans: It targets only complementary mRNA sequences.

SECTION E: Biotechnology in Medicine & Gene Therapy (Cases 19–22)

Case 19

A diabetic patient uses recombinant insulin instead of animal insulin.

Q. Why is recombinant insulin preferred?
Ans: It is pure, identical to human insulin, and does not cause allergic reactions.

Case 20

A child with ADA deficiency receives gene therapy.

Q. What is the aim of this treatment?
Ans: To restore normal immune function by introducing a functional ADA gene.

Case 21

Biotechnology enables early disease detection.

Q. How does this benefit patients?
Ans: Early diagnosis allows timely treatment and improved recovery.

Case 22

Interferons are produced using recombinant technology.

Q. State their medical importance.
Ans: Interferons help treat viral infections and certain cancers.

SECTION F: Transgenic Animals & Ethical Issues (Cases 23–25)

Case 23

A transgenic mouse is used to study cancer.

Q. Why are transgenic animals important in research?
Ans: They help understand gene function and model human diseases.

Case 24

Human proteins are extracted from milk of a genetically modified animal.

Q. Name this application.
Ans: Pharming.

Case 25

A company patents a biological product developed using native resources.

Q. Which ethical issue is involved?
Ans: Biopatenting and possible biopiracy if communities are not compensated.