Biotechnology and Its Applications: Class 12 NCERT Biology Guide

Introduction to Biotechnology and Its Applications

Biotechnology involves using living organisms or their components to develop useful products. In Class 12 NCERT Biology, this chapter focuses on how biotechnology is applied in agriculture, medicine, and industry. It helps increase food production, develop disease-resistant plants, and produce medicines like insulin. Understanding these applications is essential for students to appreciate biotechnology's role in solving real-world problems.

Micropropagation: Rapid Plant Multiplication

Micropropagation is a tissue culture technique that allows rapid multiplication of plants under sterile conditions. It uses the totipotency of plant cells, meaning any plant cell can regenerate into a whole plant when provided with the right nutrients and hormones.

Key features of micropropagation:

• Produces thousands of genetically identical plants (somaclones) quickly.
• Independent of seasonal constraints.
• Useful for commercial propagation of crops like banana, tomato, and apple.
• Helps produce virus-free plants by culturing meristematic tissue.

Components of the culture medium:

• Macronutrients (N, P, K)
• Micronutrients (Fe, Mn, Zn)
• Vitamins (thiamine)
• Carbon source (usually sucrose)
• Plant growth regulators (auxins and cytokinins)
• Gelling agent (agar)

This technique ensures high-quality, disease-free planting material, boosting agricultural productivity.

Meristem Culture for Virus-Free Plants

Meristem culture exploits the fact that viruses do not invade the rapidly dividing meristematic tissue (apical meristem) of plants. By culturing this tissue in vitro, plants regenerated are free from viral infections.

Advantages:

• Produces healthy, virus-free plants even from infected parent plants.
• Ensures higher crop yields and better quality produce.

Example: Virus-free potato plants are produced using meristem culture, helping farmers avoid losses caused by viral diseases.

Genetically Modified (GM) Crops and Their Benefits

Genetically Modified (GM) crops have altered genes to improve traits such as pest resistance, stress tolerance, and nutritional value.

Examples and benefits:

• Bt cotton: Contains Bt toxin gene from Bacillus thuringiensis, making it resistant to bollworms and reducing pesticide use.
• Golden rice: Enriched with Vitamin A to combat malnutrition.
• GM crops reduce the need for chemical fertilizers and pesticides, lowering environmental impact.

GM technology offers sustainable solutions to food security challenges.

Somatic Hybridisation: Creating Novel Plant Hybrids

Somatic hybridisation involves fusing protoplasts (plant cells without cell walls) from two different species or varieties to create hybrid plants that combine desirable traits.

Process: 1. Remove cell walls enzymatically to obtain protoplasts. 2. Fuse protoplasts from two plants using chemical or electrical methods. 3. Culture fused cells to regenerate hybrid plants.

Example: Pomato, a hybrid of tomato and potato, combines the fruiting ability of tomato with the tuber-producing trait of potato.

This technique overcomes sexual incompatibility barriers and accelerates breeding programs.

Transgenic Bacteria and Their Applications

Transgenic bacteria are genetically engineered bacteria that carry foreign genes to produce valuable products.

Example: Escherichia coli transformed with the human insulin gene produces insulin for diabetes treatment.

Advantages:

• Cost-effective production of medicines.
• Large-scale manufacturing with high purity.
• Fast growth and easy genetic manipulation.

This application of biotechnology has revolutionised medicine and industry.