NCERT Solutions for Class 12 Biology Chapter 10: Biotechnology and its Applications (NCERT 2026–27)
These Class 12 Biology Chapter 10 solutions cover Biotechnology and its Applications from the latest NCERT textbook (2026–27). Every end-of-chapter Exercise question is reproduced verbatim and answered in clear, exam-ready prose — spanning GM crops, Bt cotton, RNA interference, genetically engineered insulin, gene therapy, molecular diagnosis, transgenic animals and the ethical issues of biopiracy.
Class: 12Subject: BiologyChapter: 10Name: Biotechnology and its ApplicationsExercise: 13 questionsSession: 2026–27
Chapter 10, Biotechnology and its Applications, shows how the recombinant DNA tools learnt in the previous chapter are put to work in the real world. In agriculture, tissue culture, micropropagation, somatic hybridisation and genetically modified (GM) crops such as Bt cotton and pest-resistant plants using RNA interference (RNAi) increase yield and cut pesticide use. In medicine, recombinant therapeutics such as genetically engineered human insulin, gene therapy (illustrated by ADA deficiency), and molecular diagnosis using PCR and ELISA have transformed healthcare. Transgenic animals serve in research, biological-product manufacture, vaccine and toxicity testing. Finally, the chapter raises serious ethical issues — GEAC regulation, patents, and biopiracy of resources such as Basmati rice, neem and turmeric.
Key Concepts & Definitions
Totipotency: the capacity of a plant cell or explant to regenerate into a whole plant in a suitable nutrient medium under sterile conditions.
Micropropagation: producing thousands of genetically identical plants (somaclones) in a short time through tissue culture.
Somatic hybridisation: fusing naked protoplasts of two different plant varieties to obtain a hybrid (somatic hybrid), e.g. the pomato from potato and tomato.
GMO: a Genetically Modified Organism — a plant, bacterium, fungus or animal whose genes have been altered by manipulation.
Bt toxin / Cry proteins: insecticidal crystal proteins (coded by cry genes such as cryIAc, cryIIAb, cryIAb) made by Bacillus thuringiensis; they exist as inactive protoxins and become active in the alkaline insect gut.
RNA interference (RNAi): a cellular defence mechanism in which a complementary double-stranded RNA (dsRNA) silences a specific mRNA, preventing its translation.
Gene therapy: insertion of normal/functional genes into a person’s cells and tissues to correct a diagnosed genetic defect.
Transgenic animal: an animal whose DNA has been manipulated to possess and express an extra (foreign) gene.
Biopiracy: the use of bio-resources by multinational companies or organisations without proper authorisation from, or compensation to, the countries and people concerned.
NCERT Exercises — Full Solutions
Questions below are reproduced verbatim from the NCERT textbook (2026–27). Answers are original and written in exam-ready CBSE style.
1. Which part of the plant is best suited for making virus-free plants and why?
ANSWERThe meristem — both the apical meristem and the axillary meristem — is best suited for raising virus-free plants.Even when a plant is infected with a virus, the meristematic tissue remains free of the virus, because the virus cannot keep pace with the rapidly dividing meristem cells and these cells lack well-developed vascular connections through which the virus spreads.Therefore, the meristem is excised and grown in vitro by tissue culture to obtain healthy, virus-free plants. Scientists have used this technique successfully in banana, sugarcane and potato.
2. What is the major advantage of producing plants by micropropagation?
ANSWERThe major advantage is that a very large number of plants can be produced in a very short time from a small amount of tissue.All the plants so produced are genetically identical to the original parent plant, i.e. they are somaclones, so the desirable characters of the parent are preserved. The method also allows recovery of healthy (disease/virus-free) plants. Important food plants such as tomato, banana and apple have been raised commercially in this way.
3. Find out what the various components of the medium used for propagation of an explant in vitro are?
ANSWERThe nutrient medium used to culture an explant must supply everything the tissue needs to grow and regenerate. Its main components are:(i) a carbon source such as sucrose, to provide energy;(ii) inorganic salts (macronutrients and micronutrients);(iii) vitamins;(iv) amino acids; and(v) growth regulators such as auxins and cytokinins.The medium must be sterile, and the relative proportion of auxins to cytokinins controls whether roots or shoots are formed.
4. Crystals of Bt toxin produced by some bacteria do not kill the bacteria themselves because –
(a) bacteria are resistant to the toxin(b) toxin is immature;(c) toxin is inactive;(d) bacteria encloses toxin in a special sac.
ANSWER(c) toxin is inactive.In Bacillus thuringiensis the Bt toxin is present as an inactive protoxin in the form of crystals, so it does not harm the bacterium. When an insect ingests the protoxin, the alkaline pH of the insect gut solubilises the crystals and converts the protoxin into the active toxin. The activated toxin binds to midgut epithelial cells, creates pores, causes cell swelling and lysis, and kills the insect. As the bacterial cell does not have this alkaline gut environment, the toxin stays inactive and harmless to B. thuringiensis.
5. What are transgenic bacteria? Illustrate using any one example.
ANSWERTransgenic bacteria are bacteria whose DNA has been manipulated by recombinant DNA technology so that they carry and express one or more foreign (external) genes.Example — production of human insulin: In 1983, the company Eli Lilly prepared two DNA sequences corresponding to the A and B chains of human insulin and introduced them into plasmids of Escherichia coli. The transgenic E. coli produced the two insulin chains separately; these were then extracted and combined by creating disulphide bonds to form functional human insulin (Humulin). Thus the transgenic bacterium becomes a factory for a useful human protein.
6. Compare and contrast the advantages and disadvantages of production of genetically modified crops.
ANSWERGenetic modification of crops has many benefits but also raises concerns, summarised below.
Advantages of GM crops
Disadvantages / concerns
Made crops more tolerant to abiotic stresses such as cold, drought, salt and heat.
GM organisms released into the ecosystem may have unpredictable effects on non-target organisms and biodiversity.
Reduced reliance on chemical pesticides through pest-resistant crops (e.g. Bt cotton), lowering environmental pollution.
Possible transfer of foreign genes (e.g. to weeds) and development of resistance in pests over time.
Helped reduce post-harvest losses.
Concerns about allergies or other health effects of consuming GM food (raises bioethical questions).
Increased efficiency of mineral use by plants, preventing early exhaustion of soil fertility.
Seeds may be costly and controlled by a few companies through patents, affecting poor farmers.
Enhanced nutritional value of food, e.g. Golden Rice enriched with Vitamin A; also used to make tailor-made plants supplying starches, fuels and pharmaceuticals.
Ethical issues regarding manipulation of living organisms and reduction of natural genetic diversity.
7. What are Cry proteins? Name an organism that produce it. How has man exploited this protein to his benefit?
ANSWERCry proteins are insecticidal (toxic) crystal proteins coded by genes called cry (e.g. cryIAc, cryIIAb, cryIAb). They exist as inactive protoxins and become active toxins in the alkaline gut of insects, where they kill the insect by forming pores in midgut cells.Organism: they are produced by the soil bacterium Bacillus thuringiensis (Bt).Benefit to man: the specific cry (Bt toxin) genes have been isolated from B. thuringiensis and incorporated into crop plants, creating pest-resistant transgenic crops such as Bt cotton, Bt corn, rice, tomato, potato and soyabean. These crops kill the target insect pests on their own, so the need for chemical insecticides is greatly reduced. For example, the proteins of cryIAc and cryIIAb control cotton bollworms and cryIAb controls the corn borer.
8. What is gene therapy? Illustrate using the example of adenosine deaminase (ADA) deficiency.
ANSWERGene therapy is a collection of methods that allows the correction of a gene defect diagnosed in a child or embryo, by inserting normal/functional genes into a person’s cells and tissues to compensate for the non-functional gene and thereby treat the disease.ADA deficiency: Adenosine deaminase (ADA) is an enzyme crucial for the proper functioning of the immune system. Its deficiency, caused by the deletion of the gene for ADA, can be treated by bone marrow transplantation or by enzyme replacement therapy (injecting functional ADA), but neither is completely curative.The gene-therapy approach (first given in 1990 to a 4-year-old girl): lymphocytes from the patient’s blood are grown in culture outside the body; a functional ADA cDNA is introduced into these lymphocytes using a retroviral vector; and the engineered lymphocytes are returned to the patient. Because these cells are not immortal, the patient needs periodic infusion of such cells. A permanent cure may be possible if the gene isolated from marrow cells producing ADA is introduced into cells at early embryonic stages.
9. Diagrammatically represent the experimental steps in cloning and expressing an human gene (say the gene for growth hormone) into a bacterium like E. coli?
ANSWERThe cloning and expression of a human gene (e.g. the gene for human growth hormone) in E. coli follows these sequential steps:Step 1 — Isolate the gene of interest: the human gene coding for growth hormone is identified and isolated, or its cDNA is synthesised, and cut out using a suitable restriction endonuclease.Step 2 — Prepare the vector: a cloning vector (a plasmid of E. coli) is cut with the same restriction enzyme so that the cut ends are complementary (sticky ends) to those of the gene.Step 3 — Form recombinant DNA: the human gene is joined into the open plasmid using the enzyme DNA ligase, producing a recombinant plasmid carrying the growth-hormone gene.Step 4 — Transformation: the recombinant plasmid is introduced into competent E. coli host cells (transformation).Step 5 — Selection & multiplication: transformed cells are selected (using marker genes) and cultured in a bioreactor, where they multiply and the foreign gene is replicated (cloned) along with them.Step 6 — Expression & downstream processing: the host cells express the gene and synthesise human growth hormone, which is then extracted and purified by downstream processing.(In an exam, draw a flow diagram: human gene + vector → cut with same restriction enzyme → join with DNA ligase → recombinant plasmid → insert into E. coli → culture → product collected.)
10. Can you suggest a method to remove oil (hydrocarbon) from seeds based on your understanding of rDNA technology and chemistry of oil?
ANSWERSeed oils are triglycerides (esters of glycerol and fatty acids) made in the seed by a series of enzyme-controlled steps. Using recombinant DNA technology one can interfere with these steps to lower oil content.Method: identify the gene that codes for the key enzyme responsible for fatty-acid/triglyceride (oil) synthesis in the seed. This gene can then be silenced using the technique of RNA interference (RNAi) — introducing a construct that produces both sense and anti-sense RNA, which form a dsRNA and block translation of that gene’s mRNA. With the enzyme no longer made, oil synthesis in the seed is greatly reduced (a low-oil transgenic seed).Alternatively, a gene coding for a lipase enzyme (which hydrolyses the oil into glycerol and free fatty acids) could be expressed in the seed so that the stored oil is broken down. (Reasonable rDNA-based suggestions are accepted.)
11. Find out from internet what is golden rice.
ANSWERGolden Rice is a genetically modified variety of rice (Oryza sativa) engineered to produce and accumulate beta-carotene (pro-Vitamin A) in the edible part of the grain (the endosperm).It is created by inserting genes of the beta-carotene biosynthetic pathway into the rice plant. The accumulated beta-carotene gives the grain a characteristic golden-yellow colour, which is why it is called “golden” rice.Its purpose is to combat Vitamin A deficiency, a major cause of blindness and death among children in regions where rice is the staple food. Thus Golden Rice is an example of GM crops with enhanced nutritional value.
12. Does our blood have proteases and nucleases?
ANSWERNo. Normal human blood (plasma/serum) does not contain free, active digestive nucleases, and it has only highly regulated protease systems, not the general digestive proteases.Nucleases: blood does not carry free nucleases that would digest DNA/RNA; if it did, the body’s own nucleic acids and circulating genetic material would be destroyed.Proteases: blood does not contain free digestive proteases (such as pepsin or trypsin). The proteolytic enzymes present are kept as inactive zymogens and are tightly controlled — for example, the proteases of the blood-clotting cascade are activated only when needed. So, broadly, our blood does not have active proteases and nucleases circulating freely.
13. Consult internet and find out how to make orally active protein pharmaceutical. What is the major problem to be encountered?
ANSWERTo make a protein drug (such as insulin) orally active, the protein must be protected so it can survive the gut and still reach the bloodstream in working form. Strategies include:(i) encapsulation / enteric coating — coating the protein so it passes safely through the acidic, enzyme-rich stomach and is released in the intestine;(ii) using protease inhibitors alongside the drug to reduce its breakdown;(iii) adding absorption enhancers or chemically modifying the protein to improve its uptake across the gut wall.Major problem: proteins are broken down (digested) by the strong acid and the proteolytic enzymes of the stomach and intestine into amino acids/peptides, so the drug is destroyed before it can be absorbed. In addition, large protein molecules are poorly absorbed across the gut lining. This is why protein drugs like insulin are usually injected rather than swallowed.
Extra Practice Questions
Short Answer Type Questions
Q1. What is a somaclone?
ANSWERA somaclone is one of the many plants produced by micropropagation through tissue culture that is genetically identical to the original parent plant from which it was grown.
Q2. What is a pomato? How is it produced?
ANSWERA pomato is a somatic hybrid produced by fusing the protoplasts of a potato and a tomato and growing the hybrid protoplast into a new plant (somatic hybridisation). However, it did not have all the desired characters needed for commercial use.
Q3. Why was recombinant human insulin a major advance over animal insulin?
ANSWERInsulin extracted from the pancreas of slaughtered cattle and pigs sometimes caused allergy or immune reactions because it was a foreign protein. Recombinant human insulin made in bacteria is structurally identical to natural human insulin, so it does not provoke such unwanted immune responses.
Q4. How does PCR help in early detection of a pathogen?
ANSWERPCR amplifies the nucleic acid of a pathogen, so even a very low concentration of a bacterium or virus — present before any disease symptoms appear — can be detected. PCR is routinely used to detect HIV in suspected AIDS patients and mutations in suspected cancer patients.
Q5. What is the role of GEAC?
ANSWERGEAC (Genetic Engineering Approval Committee) is an Indian Government body that makes decisions regarding the validity of GM research and the safety of introducing GM organisms for public services.
Long Answer Type Questions
Q1. Explain how RNA interference (RNAi) is used to develop a nematode-resistant tobacco plant.
ANSWERThe nematode Meloidogyne incognitia infects the roots of tobacco plants and greatly reduces yield. To protect the plant, scientists used the natural defence mechanism of RNA interference (RNAi), in which a complementary dsRNA silences a specific mRNA and prevents its translation. Using Agrobacterium as a vector, nematode-specific genes were introduced into the tobacco plant in such a way that the host cells produced both sense and anti-sense RNA. Being complementary, these formed a double-stranded RNA (dsRNA) that triggered RNAi and silenced the specific mRNA of the nematode. As a result, the parasite could not survive in the transgenic host, and the plant was protected from infestation without using chemicals.
Q2. Describe the various uses of transgenic animals.
ANSWERTransgenic animals (over 95% of which are mice) are produced for several purposes: (i) Normal physiology and development — to study how genes are regulated and how they affect body functions and development, e.g. insulin-like growth factor. (ii) Study of disease — they serve as models of human diseases such as cancer, cystic fibrosis, rheumatoid arthritis and Alzheimer’s, helping investigate new treatments. (iii) Biological products — they can be engineered to produce useful, otherwise expensive products; e.g. the transgenic cow Rosie (1997) gave human protein-enriched milk containing human alpha-lactalbumin. (iv) Vaccine safety — transgenic mice are used to test the safety of vaccines (e.g. the polio vaccine), potentially replacing monkeys. (v) Chemical safety testing (toxicity testing) — transgenic animals made more sensitive to toxins give faster toxicity results.
Q3. What is biopiracy? Why is it a matter of concern for India? Give examples.
ANSWERBiopiracy is the use of bio-resources by multinational companies and other organisations without proper authorisation from the countries and people concerned and without compensatory payment. Industrialised nations are financially rich but poor in biodiversity and traditional knowledge, whereas developing countries like India are rich in both. This creates injustice and inadequate benefit-sharing. Examples: in 1997 an American company obtained US patent rights on Basmati rice (a crop with about 27 documented Indian varieties and ancient roots), and attempts have been made to patent products and processes based on turmeric and neem. To counter this, India has cleared the second amendment of the Indian Patents Bill to safeguard its bio-resources and traditional knowledge.
Multiple Choice Questions (MCQs)
1. The capacity to generate a whole plant from any cell or explant is called:
For each Assertion–Reason question, choose: (A) Both true and the Reason correctly explains the Assertion; (B) Both true but the Reason is not the correct explanation; (C) Assertion true, Reason false; (D) Assertion false, Reason true.
A-R 1. Assertion: The meristem is used to obtain virus-free plants.
Reason: Even in a virus-infected plant, the apical and axillary meristems remain free of the virus.
A-R 2. Assertion: The Bt toxin does not kill the Bacillus thuringiensis that produces it.
Reason: In the bacterium the toxin exists as an inactive protoxin and is activated only in the alkaline gut of an insect.
A-R 3. Assertion: Insulin is generally administered to diabetic patients by injection rather than orally.
Reason: As a protein, oral insulin would be digested by the proteolytic enzymes of the gut before it could act.
A-R 4. Assertion: Recombinant human insulin produced in bacteria can trigger strong immune reactions in humans.
Reason: Recombinant human insulin is structurally identical to natural human insulin.
A-R 5. Assertion: PCR can detect a pathogen even before disease symptoms appear.
Reason: PCR amplifies the very small amount of nucleic acid of the pathogen to a detectable level.
Answer key: 1-(A), 2-(A), 3-(A), 4-(D), 5-(A).
Common Mistakes to Avoid
Watch out for these
Confusing somaclones (genetically identical micropropagated plants) with somatic hybrids (made by protoplast fusion of two varieties).
Saying the Bt toxin is “always active” — it exists as an inactive protoxin and is activated only in the insect’s alkaline gut.
Mixing up the cry genes: cryIAc / cryIIAb control cotton bollworms, while cryIAb controls the corn borer.
Writing that gene therapy permanently cures ADA deficiency when lymphocytes are used — it requires repeated infusions because the cells are not immortal.
Stating that recombinant human insulin causes immune reactions — it is identical to human insulin, so it does not; it was the animal insulin that caused allergies.
Confusing the diagnostic tools: PCR amplifies nucleic acid, while ELISA uses antigen–antibody interaction.
Exam tips for this chapter
Learn the small but high-scoring facts examiners love: meristem → virus-free plants; cry gene names and their target pests; Eli Lilly + E. coli + 1983 for insulin; ADA deficiency + retroviral vector + 1990 for gene therapy; Rosie the cow + alpha-lactalbumin + 1997; GEAC for regulation; and the Basmati/turmeric/neem examples for biopiracy. For the “cloning a human gene” question, always draw a clean labelled flow diagram and mention the same restriction enzyme, DNA ligase, transformation, selection and downstream processing. Write answers point-wise and underline the keywords.
Frequently Asked Questions
What is Class 12 Biology Chapter 10 about?
Chapter 10, Biotechnology and its Applications, covers how recombinant DNA technology is applied in agriculture (tissue culture, micropropagation, GM crops, Bt cotton, RNAi-based pest resistance) and in medicine (recombinant insulin, gene therapy, PCR and ELISA diagnosis), along with transgenic animals and the ethical issues such as biopiracy and patents.
How many questions are there in the NCERT exercise of Chapter 10?
The end-of-chapter Exercise has 13 questions, all reproduced verbatim and fully answered on this page, including the MCQ-type Q4 and the diagram-based Q9.
Why is human insulin produced in bacteria preferred over animal insulin?
Insulin from cattle and pigs sometimes caused allergic or immune reactions because it is a foreign protein. Recombinant human insulin made in E. coli is structurally identical to natural human insulin, so it does not trigger such unwanted immune responses and can be produced in large quantities.
Are these Class 12 Biology Chapter 10 solutions free?
Yes. All ClearStudy NCERT Solutions for Class 12 Biology are free and follow the official NCERT textbook for the 2026–27 session.
