Class 12 Chapter 10 Biotechnology and Its Applications Solutions. Explore Class 12 Biology Chapter 10 Biotechnology and Its Applications Solutions with easy-to-understand answers, important questions, and exam-focused explanations to master key concepts, revise effectively, and prepare confidently for exams.
Class 12 Biology Chapter 10 Biotechnology and Its Applications Solutions
A. Very Short-Answer Questions (Biotechnology and Its Applications Solutions)
- What are genetically modified organisms?
Answer: Organisms such as plants, bacteria, fungi, and animals whose genes have been deliberately altered using genetic engineering are called genetically modified organisms (GMOs).
- Name a vaccine prepared using a genetically engineered antigen.
Answer: Hepatitis B vaccine.
- What controls biological toxicity in Bt crops?
Answer: The cry gene (a gene encoding the Bt toxin).
- What is Agrobacterium used for?
Answer: Agrobacterium is used as a vector to transfer desired genes into plant cells.
- How can adenosine deaminase (ADA) deficiency in children be treated?
Answer: It can be treated by bone-marrow transplantation. The source also discusses gene therapy and enzyme replacement as treatment approaches.
- How can a DNA clone be detected using a probe?
Answer: A DNA or RNA probe is labelled, allowed to hybridize with its complementary DNA sequence, and detected by autoradiography or another suitable detection method.
- How many polypeptide chains are present in human insulin?
Answer: Two.
- What are transgenic animals?
Answer: Transgenic animals are animals whose DNA has been altered by introducing a foreign gene that is expressed in the animal.
- What is special about the milk produced by the transgenic cow Rosie? (H.S. 2024)
Answer: Rosie produced milk enriched with human alpha-lactalbumin. The source describes it as more nutritionally suitable for infants than ordinary cow’s milk.
- What is Golden Rice?
Answer: Golden Rice is a genetically engineered variety of rice that produces beta-carotene, a precursor of vitamin A.
Fill in the blanks (Biotechnology and Its Applications Solutions)
- In mammals, including humans, insulin is synthesized as a ______.
Answer: Prohormone.
- The milk of a transgenic cow contains human ______.
Answer: Alpha-lactalbumin.
- The first transgenic crop was ______.
Answer: Bt cotton.
- Genetically engineered human insulin is called ______.
Answer: Humulin.
- Bacillus thuringiensis produces ______ that kills insect pests.
Answer: A toxin (Bt toxin).
- Biopiracy is often carried out by ______ countries.
Answer: Developed countries (as stated in the source).
- The fusion of a lymphocyte and a tumour cell is called a ______.
Answer: Hybridoma.
- The soil bacterium ______ produces the Bt crystal protein.
Answer: Bacillus thuringiensis.
B. Short-Answer Questions (2 marks each)
- What is the importance of recombinant DNA technology in healthcare?
Answer: Recombinant-DNA technology enables the large-scale production of safe and effective therapeutic substances. Products made by this method can be identical or very similar to natural human proteins and may reduce unwanted immune reactions. Human insulin, for example, can be produced by bacteria while retaining the structure of human insulin.
- What are the advantages of genetically modified (GM) plants?
Answer: GM plants can increase crop yield, reduce post-harvest losses, and improve resistance to different stresses. Some GM plants have improved nutritional value and can reduce dependence on chemical pesticides.
- What are the three major areas of research in biotechnology?
Answer: (i) Providing improved organisms or biological agents, such as microorganisms and enzymes, as useful catalysts. (ii) Using engineering to create optimal conditions for these biological catalysts to function. (iii) Developing downstream-processing technologies to separate and purify proteins or other biological compounds.
- How does the production of transgenic plants differ from conventional plant breeding?
Answer: Transgenic crops are produced by genetic engineering: a gene associated with a desired trait, sometimes from another species, is isolated and inserted into the crop’s DNA. This can introduce a specific trait that may not be readily obtainable through conventional breeding.
- What are the outcomes or benefits of genetic modification?
Answer: (i) Greater resistance to abiotic stresses. (ii) Reduced reliance on chemical pesticides. (iii) Reduced post-harvest losses. (iv) Improved efficiency of mineral use. (v) Improved nutritional value of food.
- Describe the uses of transgenic animals in the following areas: (a) normal physiology and development; (b) biological products; (c) testing chemical safety.
Answer: (a) Normal physiology and development: Transgenic animals can be developed to study how genes are regulated and how they affect normal body functions and development. They can also help researchers study the effects of genes from other species and the biological roles of particular genes. (b) Biological products: Transgenic animals may be engineered to produce useful human proteins or other biological products for medical treatment. Research has explored possible treatments involving proteins for conditions such as emphysema, phenylketonuria, and cystic fibrosis. (c) Chemical safety testing: Transgenic animals can be used to test the toxicity or safety of chemicals. Some are designed to be more sensitive to toxic substances, allowing researchers to observe effects in a shorter period.
- What is molecular diagnosis? What are its advantages?
Answer: Conventional diagnosis may identify an infection only after symptoms appear, when the pathogen may already have multiplied considerably. Molecular diagnosis can detect very small amounts of viral or bacterial genetic material, making it possible to identify infection earlier and more sensitively.
C. Descriptive Questions (3–5 marks each)
- What is gene therapy? Explain it using the example of adenosine deaminase (ADA) deficiency. (H.S. 2024)
Answer: Gene therapy is a treatment approach in which a functional gene is introduced into a patient’s cells or tissues to compensate for a defective gene. ADA deficiency can sometimes be treated by bone-marrow transplantation; enzyme replacement is another option. In the gene-therapy approach described in the source, lymphocytes are collected from the patient and grown outside the body. A functional ADA cDNA is introduced into these cells using a vector, and the modified cells are then returned to the patient. If the functional gene is introduced into suitable cells that persist and continue to express it, the treatment may provide longer-lasting benefit; introducing it into cells with a limited lifespan may require repeated treatment.
- What is Cry protein? Which organism produces it, and how has it benefited humans?
Answer: Cry proteins are insecticidal proteins encoded by cry genes and produced by the bacterium Bacillus thuringiensis (Bt). In the bacterium, the protein is present in an inactive form. When an insect larva ingests it, the alkaline conditions in the insect gut activate the toxin. It damages the gut lining and can kill the insect. Genes encoding Bt toxins have been introduced into crops such as Bt cotton and Bt maize, helping protect them against certain insect pests and potentially reducing the need for chemical insecticides.
- Explain the importance of transgenic animals in medicine.
Answer: Transgenic animals are useful in biomedical research and medicine. They can help researchers study gene function, normal physiology, and disease development. They can also be used to investigate the safety and effectiveness of vaccines and to produce certain biological products. They provide models for studying the effects of toxic substances and for understanding disease resistance and other medically relevant traits.
- Describe the benefits of genetically modified plants for overall crop improvement.
Answer: (i) They can improve resistance to abiotic stresses. (ii) They can reduce dependence on chemical pesticides. (iii) They can reduce post-harvest losses. (iv) They can improve the plant’s ability to use minerals. (v) They can increase the nutritional value of food.
D. Additional Questions and Answers (Biotechnology and Its Applications Solutions)
- Name a crop with enhanced nutritional value.
Answer: Golden Rice.
- What is the main component encoded by the Bt toxin gene?
Answer: The cry gene encodes an insecticidal crystal protein (Bt Cry protein).
- What is gene therapy?
Answer: Gene therapy is a treatment method that introduces a functional gene into cells or tissues to compensate for or replace the function of a defective gene. It may involve introducing a working gene into target cells so that they can produce the required functional product.
- Why is insulin produced using bacteria rather than extracted from animal sources?
Answer: Historically, insulin was extracted from the pancreases of cattle and pigs. Animal insulin can differ slightly from human insulin and may cause immune or allergic reactions in some patients. Recombinant-DNA technology allows human insulin to be produced using microorganisms.
- What measures can help prevent biopiracy?
Answer: Legal protections and international agreements can regulate access to biological resources and associated traditional knowledge, helping prevent their unauthorized use.
- What problems can arise in patenting biological resources or traditional knowledge?
Answer: (i) Traditional agricultural practices or biological resources may be claimed through patents by parties outside the communities or countries where they originated. (ii) Some inventions may already have been patented, creating conflicts over ownership or novelty. (iii) Traditional natural medicines or knowledge may be patented by companies or researchers without appropriate recognition or benefit-sharing.
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