CBSE Class 12 Biology (2026–27)
Chapter 10: Biotechnology and Its Applications
20 Important Questions and Answers
The chapter focuses on applications of biotechnology in agriculture, medicine, transgenic animals, molecular diagnosis, biosafety, biopiracy, and patents. Key topics include Bt crops, RNA interference (RNAi), recombinant insulin, gene therapy, molecular diagnosis, transgenic animals, and ethical issues.
1. What are genetically modified (GM) crops? Mention their advantages.
Answer:
Genetically Modified (GM) crops are plants whose genetic material has been altered using genetic engineering techniques to introduce desirable traits. These crops may possess resistance to pests, diseases, herbicides, or environmental stress. Examples include Bt cotton and Golden Rice. GM crops reduce dependence on chemical pesticides, improve crop yield, and enhance nutritional quality. They can also increase shelf life and tolerance to adverse environmental conditions. Such modifications help farmers reduce production costs and contribute to sustainable agriculture. GM technology is widely used to address food security issues and improve agricultural productivity while minimizing environmental damage caused by excessive agrochemical use.
2. Explain the role of Bt toxin in pest-resistant plants.
Answer:
Bt toxin is produced by the bacterium Bacillus thuringiensis (Bt). The toxin is encoded by cry genes, which are transferred into crop plants through genetic engineering. When insect larvae feed on Bt plants, the inactive protoxin becomes activated in the alkaline environment of the insect gut. The activated toxin binds to gut epithelial cells, creating pores that cause cell lysis and death of the insect. Different cry genes target specific insects. For example, cryIAc and cryIIAb genes are used against cotton bollworms. Bt crops reduce pesticide usage, lower production costs, and provide effective biological pest control, making agriculture more environmentally friendly.
3. What is RNA interference (RNAi)? How is it used in biotechnology?
Answer:
RNA interference (RNAi) is a natural cellular mechanism that suppresses gene expression by degrading specific messenger RNA (mRNA) molecules. It occurs when double-stranded RNA (dsRNA) enters a cell and triggers the destruction of complementary mRNA. In biotechnology, RNAi has been used to develop pest-resistant plants. A notable example is tobacco plants engineered to resist the nematode Meloidogyne incognita. The introduced genes produce dsRNA corresponding to essential nematode genes, thereby silencing them and preventing infection. RNAi offers a precise and environmentally safe method for controlling pests without relying heavily on chemical pesticides, contributing to sustainable agriculture.
4. Describe the production of human insulin using recombinant DNA technology.
Answer:
Human insulin is produced through recombinant DNA technology using genetically engineered bacteria. Insulin consists of two polypeptide chains, A and B, connected by disulfide bonds. Scientists synthesized DNA sequences for both chains and inserted them separately into plasmids of Escherichia coli. The bacteria produced the A and B chains independently. After extraction, the two chains were joined chemically to form functional insulin. This recombinant insulin, marketed as Humulin, was the first genetically engineered pharmaceutical product. It is safer and more effective than insulin extracted from animal sources because it closely resembles natural human insulin and reduces allergic reactions in diabetic patients.
5. What is gene therapy? Explain ADA deficiency treatment.
Answer:
Gene therapy is a technique used to treat genetic disorders by introducing a normal functional gene into a patient’s cells. One of the earliest examples involves ADA (Adenosine Deaminase) deficiency, which causes Severe Combined Immunodeficiency (SCID). In this disorder, the immune system becomes severely weakened. During treatment, lymphocytes are isolated from the patient and cultured outside the body. A functional ADA gene is introduced into these cells using a suitable vector. The modified cells are then returned to the patient, where they produce the ADA enzyme. This therapy improves immune function and demonstrates the potential of biotechnology in treating inherited diseases.
6. What are transgenic animals? Give two examples.
Answer:
Transgenic animals are animals whose genomes have been modified by introducing foreign genes using genetic engineering techniques. These animals express new traits that are not naturally present. One example is Rosie, a transgenic cow that produced milk enriched with human alpha-lactalbumin protein. Another example is transgenic mice used in biomedical research. Transgenic animals help scientists study gene function, understand disease mechanisms, test vaccine safety, and produce valuable biological products. They also serve as models for human diseases and contribute significantly to advances in medicine, agriculture, and biotechnology research. Their development has expanded the practical applications of genetic engineering.
7. State any four uses of transgenic animals.
Answer:
Transgenic animals have several important applications in biotechnology. First, they help study normal physiology and gene regulation. Second, they serve as models for understanding human diseases such as cancer and Alzheimer’s disease. Third, they are used to produce biological products like therapeutic proteins in milk. Fourth, they play a major role in testing vaccine safety and evaluating new drugs before human trials. Additionally, transgenic animals assist in chemical safety testing and biomedical research. Their use has greatly improved scientific understanding of genetics and disease mechanisms while contributing to the development of safer medicines and vaccines.
8. What is molecular diagnosis? Mention two techniques used.
Answer:
Molecular diagnosis refers to the detection of diseases at the molecular level by identifying specific genes, DNA sequences, proteins, or pathogens. It allows early diagnosis before visible symptoms appear. Two important techniques used are Polymerase Chain Reaction (PCR) and Enzyme-Linked Immunosorbent Assay (ELISA). PCR amplifies specific DNA sequences, enabling the detection of pathogens even in very small quantities. ELISA detects antigens or antibodies in blood samples and is commonly used for diagnosing infectious diseases. Molecular diagnosis provides accurate, rapid, and sensitive disease detection, which helps in early treatment and effective disease management in modern healthcare systems.
9. Explain the principle of PCR in disease diagnosis.
Answer:
Polymerase Chain Reaction (PCR) is a technique used to amplify a specific DNA segment millions of times in a short period. It involves repeated cycles of DNA denaturation, primer annealing, and DNA synthesis. In disease diagnosis, PCR can detect the DNA of pathogens even when their numbers are extremely low. This makes it highly sensitive and useful for identifying infections at an early stage. PCR is widely used to diagnose diseases such as HIV infection, tuberculosis, and genetic disorders. The ability to detect minute quantities of genetic material makes PCR one of the most powerful tools in molecular biology and medical diagnostics.
10. What is ELISA? How is it useful?
Answer:
ELISA (Enzyme-Linked Immunosorbent Assay) is a laboratory technique used to detect specific antigens or antibodies in biological samples. It is based on antigen-antibody interactions and uses enzyme-linked markers that produce a measurable color change. ELISA is widely employed for diagnosing infectious diseases such as HIV, hepatitis, and COVID-related infections. It can detect infections even before severe symptoms develop. The method is highly sensitive, specific, and suitable for large-scale screening. ELISA also plays an important role in research laboratories and hospitals by helping monitor immune responses and identify disease-causing organisms quickly and accurately.
11. What is biopiracy? Give an example.
Answer:
Biopiracy refers to the unauthorized use, exploitation, or patenting of biological resources and traditional knowledge belonging to a country or indigenous community without proper permission or compensation. It often involves multinational companies obtaining patents on products derived from plants, animals, or traditional medicinal practices. A well-known example is the patenting attempts involving neem and turmeric, both of which have been used in India for centuries. Such actions raised concerns about the unfair exploitation of traditional knowledge. Biopiracy highlights the need for international regulations and legal protection to ensure fair sharing of benefits arising from biological resources.
12. Differentiate between biopiracy and patent.
Answer:
A patent is a legal right granted to an inventor for a new and useful invention, providing exclusive rights to produce or sell it for a specified period. It encourages innovation and protects intellectual property. Biopiracy, on the other hand, involves obtaining patents or commercial benefits from biological resources or traditional knowledge without authorization or benefit-sharing. While patents are legitimate legal protections, biopiracy is considered unethical because it exploits indigenous knowledge and biodiversity. Proper patent systems should ensure that original knowledge holders receive recognition and economic benefits. Thus, the key difference lies in legality, ethics, and fair ownership of biological resources.
13. What is GEAC? Mention its functions.
Answer:
GEAC (Genetic Engineering Appraisal Committee) is the regulatory body in India responsible for evaluating and approving activities involving genetically modified organisms (GMOs). Its primary role is to assess the environmental and health impacts of genetically engineered products before their release. GEAC ensures biosafety by monitoring field trials, commercial cultivation, and research involving GM organisms. It also establishes guidelines for the safe handling and use of biotechnology products. Through scientific evaluation and regulation, GEAC helps balance technological advancement with environmental protection and public safety. Its decisions are crucial for the responsible application of genetic engineering in agriculture and medicine.
14. Why are biosafety measures necessary for GM organisms?
Answer:
Biosafety measures are essential to ensure that genetically modified organisms (GMOs) do not adversely affect human health, biodiversity, or the environment. GM crops may potentially transfer genes to wild relatives, affect non-target organisms, or create ecological imbalances. Biosafety regulations involve risk assessment, controlled field trials, monitoring, and regulatory approval before commercial release. These measures help identify possible hazards and ensure safe use of biotechnology products. Proper biosafety practices also build public confidence in genetic engineering technologies. Therefore, biosafety serves as a precautionary framework that promotes the responsible development and application of modern biotechnology.
15. How do Bt crops help farmers?
Answer:
Bt crops contain genes from Bacillus thuringiensis that produce insecticidal proteins capable of killing specific pests. These crops provide built-in protection against insect attacks, reducing the need for chemical pesticides. As a result, farmers spend less on pest control and experience lower crop losses. Reduced pesticide use also minimizes environmental pollution and protects beneficial insects. Higher crop yields and improved quality contribute to better economic returns. Bt cotton is a widely cultivated example that has significantly reduced bollworm damage. Thus, Bt crops promote sustainable agriculture by combining effective pest management with increased productivity and environmental conservation.
16. What are the advantages of recombinant therapeutic proteins?
Answer:
Recombinant therapeutic proteins are produced using genetically engineered microorganisms or cell cultures. These proteins offer several advantages over conventional sources. They are highly pure, safe, and free from contamination by human or animal pathogens. Large-scale production is possible, ensuring a consistent supply. Recombinant proteins closely resemble natural human proteins, reducing the risk of allergic reactions. Examples include insulin, growth hormone, and blood-clotting factors. Their production through biotechnology has revolutionized medical treatment by providing effective therapies for chronic diseases and genetic disorders. Consequently, recombinant therapeutic proteins represent a major achievement in modern biotechnology and healthcare.
17. Why is recombinant insulin preferred over animal insulin?
Answer:
Recombinant insulin is preferred because it is structurally identical to human insulin and is produced through genetic engineering. Animal insulin, obtained from pigs or cattle, may differ slightly in amino acid sequence and can sometimes cause allergic reactions. Recombinant insulin is highly pure, safe, and available in large quantities. Its production avoids dependence on animal sources and reduces the risk of contamination. It also ensures consistent quality and effectiveness for diabetic patients. Since its introduction, recombinant insulin has become the standard treatment worldwide and remains one of the most successful applications of biotechnology in medicine.
18. What are the major applications of biotechnology in medicine?
Answer:
Biotechnology has transformed medicine through the development of recombinant therapeutic proteins, vaccines, gene therapy, stem cell technology, and molecular diagnostic tools. Recombinant insulin is used to treat diabetes, while recombinant vaccines help prevent infectious diseases. Gene therapy offers treatment possibilities for inherited disorders such as ADA deficiency. Molecular diagnostic techniques like PCR and ELISA enable early disease detection. Biotechnology also supports the production of monoclonal antibodies and other therapeutic agents. These applications improve diagnosis, prevention, and treatment of diseases while enhancing healthcare quality. Thus, biotechnology plays a crucial role in advancing modern medical science and patient care.
19. What ethical issues are associated with biotechnology?
Answer:
Biotechnology raises several ethical concerns regarding the use of genetically modified organisms, transgenic animals, and genetic manipulation. Questions arise about environmental safety, biodiversity conservation, food security, and long-term health effects of GM products. Ethical issues also include animal welfare during the creation of transgenic animals and equitable sharing of benefits from biological resources. Biopiracy and patenting of traditional knowledge are major concerns, particularly for developing countries. Regulatory authorities and international agreements seek to address these issues through biosafety guidelines and legal frameworks. Ethical considerations ensure that biotechnology advances responsibly and benefits society as a whole.
20. Write a short note on Golden Rice.
Answer:
Golden Rice is a genetically modified rice variety developed to combat vitamin A deficiency, a major public health problem in many developing countries. Scientists introduced genes responsible for beta-carotene synthesis into rice endosperm. Beta-carotene is a precursor of vitamin A and gives the grains a characteristic golden-yellow color. Consumption of Golden Rice can help reduce vitamin A deficiency, which is associated with blindness and weakened immunity. It represents a significant application of biotechnology in improving nutritional quality, a concept known as biofortification. Golden Rice demonstrates how genetic engineering can address malnutrition and contribute to global food and health security.