Biotechnology is one of the most important branches of modern biology that deals with the use of living organisms, cells, enzymes, or biological systems to develop useful products and technologies for human welfare. In Class 12 Biology, the chapter “Biotechnology and Its Applications Class 12 Notes focuses on how biotechnological tools are applied in areas such as medicine, agriculture, environment, and industry. This chapter is extremely important for CBSE Board Exams, NEET, and other competitive exams, as many direct and application-based questions are frequently asked from it.
Biotechnology has revolutionized healthcare by enabling the production of life-saving drugs like insulin, vaccines, antibiotics, and hormones. It has also played a major role in improving crop productivity, pest resistance, and nutritional quality of food. In these notes, every topic of Biotechnology and Its Applications Class 12 Notes is explained in a simple, detailed, and exam-oriented manner to help students understand concepts clearly and score high marks.
Biotechnology and Its Applications Class 12 Notes PDF | NCERT + Important Questions
Applications of Biotechnology in Medicine
Medical biotechnology deals with the use of biotechnological techniques for diagnosis, prevention, and treatment of diseases. Some of the most important applications in medicine are discussed below.
1. Production of Insulin
Diabetes mellitus is a disease caused due to insufficient production of insulin by the pancreas. Earlier, insulin was extracted from the pancreas of slaughtered cows and pigs. This method had several limitations such as allergic reactions and limited availability.
With the advancement of biotechnology, human insulin is now produced using recombinant DNA technology. The human insulin gene is introduced into a bacterium (usually Escherichia coli), which then produces insulin identical to natural human insulin.
Human insulin consists of two polypeptide chains:
- Chain A (21 amino acids)
- Chain B (30 amino acids)
In bacteria, these chains are produced separately and later joined to form functional insulin. The genetically engineered insulin is marketed under the trade name Humulin.
Advantages of recombinant insulin:
- Identical to human insulin
- No allergic reactions
- Available in large quantities
- Cost-effective and safe
2. Gene Therapy
Gene therapy is a technique used to correct genetic defects by introducing a normal gene into the cells of an individual to replace or compensate for a defective gene.
One of the first successful examples of gene therapy was carried out for Adenosine Deaminase (ADA) deficiency. ADA deficiency is a genetic disorder that causes severe combined immunodeficiency (SCID), leading to a weakened immune system.
Steps involved in gene therapy for ADA deficiency:
- Lymphocytes are isolated from the patient’s blood.
- A functional ADA gene is introduced into these lymphocytes using a viral vector.
- The genetically modified lymphocytes are cultured in the laboratory.
- These modified cells are then reintroduced into the patient’s body.
Although this method provides temporary relief, permanent cure can be achieved if the functional gene is introduced at an early embryonic stage.
3. Molecular Diagnosis
Early and accurate diagnosis of diseases is essential for effective treatment. Biotechnology has provided advanced molecular diagnostic techniques that are highly sensitive and specific.
(a) Polymerase Chain Reaction (PCR)
PCR is a technique used to amplify a specific segment of DNA. It helps in detecting diseases at a very early stage, even before symptoms appear.
Applications of PCR:
- Detection of HIV in suspected AIDS patients
- Diagnosis of genetic disorders
- Identification of pathogenic microorganisms
(b) Enzyme-Linked Immunosorbent Assay (ELISA)
ELISA is based on antigen-antibody interaction. It is widely used for detecting the presence of antigens or antibodies in blood samples.
Uses of ELISA:
- HIV testing
- Pregnancy tests
- Detection of infectious diseases
Applications of Biotechnology in Agriculture
Agricultural biotechnology aims to improve crop yield, resistance to pests, tolerance to environmental stress, and nutritional quality of food.
1. Genetically Modified (GM) Crops
Genetically modified crops are plants whose genes have been altered using genetic engineering techniques to introduce desirable traits.
Some commonly developed traits include:
- Pest resistance
- Herbicide tolerance
- Disease resistance
- Improved nutritional quality
2. Bt Crops
Bt crops are genetically modified plants that produce toxins derived from the bacterium Bacillus thuringiensis (Bt). These toxins are harmful to specific insect pests but harmless to humans and animals.
The Bt toxin gene is introduced into the plant genome, enabling the plant to produce the toxin itself.
Examples of Bt crops:
- Bt cotton
- Bt maize
Mechanism of action of Bt toxin:
- Bt toxin exists as an inactive protoxin in bacteria.
- When ingested by insects, it gets activated in the alkaline gut.
- The activated toxin binds to epithelial cells of the gut.
- This creates pores in the gut lining, causing cell lysis and death of the insect.
3. Pest-Resistant Plants (RNA Interference)
RNA interference (RNAi) is a natural defense mechanism in eukaryotic organisms. It involves the silencing of specific genes by introducing double-stranded RNA.
This technique is used to develop pest-resistant plants by preventing the expression of essential genes in pests.
Example:
- Nematode-resistant tobacco plants developed using RNAi technology.
Applications of Biotechnology in Environment
Biotechnology plays a crucial role in environmental protection and sustainability.
1. Bioremediation
Bioremediation is the use of microorganisms to clean up environmental pollutants such as oil spills, heavy metals, and toxic chemicals.
Microbes can degrade harmful substances into non-toxic compounds, thereby reducing environmental pollution.
2. Sewage Treatment
Biotechnology is used in sewage treatment plants where microorganisms break down organic waste and help in recycling nutrients.
Activated sludge process is commonly used for this purpose.
Transgenic Animals
Transgenic animals are animals that have been genetically modified to carry and express foreign genes.
Applications of Transgenic Animals:
- To study gene regulation and expression
- To understand human diseases
- To produce useful biological products like proteins and hormones
- For vaccine safety testing
- For chemical safety testing
Example:
- Rosie, the first transgenic cow, produced human protein-enriched milk.
Ethical Issues Related to Biotechnology
The rapid advancement of biotechnology has raised several ethical, social, and legal concerns.
1. Bioethics
Bioethics deals with the moral principles governing the use of biotechnology.
2. Biopiracy
Biopiracy refers to the unauthorized use of biological resources and traditional knowledge without proper compensation to indigenous communities.
3. Patents
Biotechnological products and processes can be patented to protect intellectual property rights. However, patenting life forms has raised ethical debates.
Importance of Biotechnology and Its Applications (Exam Point of View)
- Helps in the production of life-saving drugs
- Improves agricultural productivity
- Protects environment
- Provides solutions for genetic disorders
- Frequently asked chapter in CBSE and NEET exams
Conclusion
The chapter Biotechnology and Its Applications Class 12 highlights how modern biological techniques are transforming medicine, agriculture, and environmental management. From producing recombinant insulin and vaccines to developing pest-resistant crops and cleaning polluted environments, biotechnology has become an integral part of human life. A clear understanding of this chapter not only helps students score well in exams but also builds awareness about the future scope of biotechnology. These detailed notes are designed to provide conceptual clarity, exam relevance, and complete coverage of the NCERT syllabus.
Important Questions – Biotechnology and Its Applications Class 12 Notes (Repeated in Exams)
Very Short Answer Questions (1 Mark)
- What is recombinant insulin?
- Name the bacterium used for the production of human insulin.
- What is ADA deficiency?
- Expand PCR.
- What is ELISA used for?
- Name the bacterium from which Bt toxin is obtained.
- What are transgenic animals?
- Define bioremediation.
Short Answer Questions (2–3 Marks)
- Why is recombinant insulin preferred over animal insulin?
- Explain the principle of PCR.
- What is gene therapy? Give one example.
- Write any two applications of ELISA.
- What is Bt cotton? Mention its advantage.
- Explain RNA interference (RNAi).
- What is biopiracy?
- Write two uses of transgenic animals.
Long Answer Questions (4–5 Marks)
- Describe the production of human insulin using recombinant DNA technology.
- Explain gene therapy with reference to ADA deficiency.
- Describe Bt toxin and its mode of action.
- Explain the applications of biotechnology in agriculture.
- What are transgenic animals? Write their applications.
- Discuss ethical issues related to biotechnology.
Case-Based / Application-Based Questions
- A child is suffering from severe immunodeficiency due to ADA deficiency. How can biotechnology help in its treatment?
- Farmers are facing heavy loss due to insect pests. How can Bt crops help solve this problem?
- How does molecular diagnosis help in early detection of diseases like AIDS?
Frequently Asked HOT Questions (Board + NEET)
- Why is insulin produced in bacteria not in human cells directly?
- How is PCR better than conventional diagnostic methods?
- Why Bt toxin does not harm humans?
- What is the difference between gene therapy and conventional treatment?
- How does biotechnology contribute to environmental protection?
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