NCERT Solutions for Class 12 Biology Chapter 8: Microbes in Human Welfare
NCERT Solutions for Class 12 Biology Chapter 8 – Microbes in Human Welfare are prepared to help students understand how tiny organisms play a massive role in our daily lives. From the curd in your kitchen to the medicines in hospitals, microbes are everywhere. Myclass24 brings you well-structured, exam-focused solutions that make every concept clear and every answer precise. Students must check all subjects NCERT solutions for Class 12 and all the chapters of NCERT solutions for class 12 Biology.
Find the PDF of NCERT Solutions for Class 12 Biology Chapter 8
Students can download the free PDF of NCERT Solutions for Class 12 Biology Chapter 8 – Microbes in Human Welfare from the Myclass24 website. The PDF is available in a clean, printable format. All solutions are structured to match the CBSE marking scheme, making them ideal for last-minute revision and exam preparation.
Chapter 8 Details at a Glance
Detail | Information |
Chapter Number | Chapter 8 |
Chapter Name | Microbes in Human Welfare |
Subject | Biology |
Class | Class 12 |
Board | CBSE / NCERT |
Total Exercises | 3 (In-text + End-of-chapter) |
Key Topics | Microbes in household products, industrial uses, sewage treatment, biogas, biocontrol, biofertilisers |
Difficulty Level | Moderate |
About Chapter 8: Microbes in Human Welfare
Chapter 8 is one of those chapters that surprises students — most people think of bacteria and fungi as harmful, but this chapter flips that idea entirely. You learn that the same microorganisms that cause diseases are also the ones fermenting your idli batter, producing antibiotics, and cleaning up sewage.
The chapter begins with microbes found in household products. Lactobacillus, for instance, is responsible for the fermentation of milk into curd. Baker's yeast (Saccharomyces cerevisiae) makes bread rise. These are everyday examples that make the content relatable. Students are often asked in exams about the specific microorganism used in a process, so these names must be remembered carefully.
Industrial and Medicinal Uses of Microbes
Moving into industrial applications, the chapter covers how microbes produce beverages, organic acids, enzymes, and bioactive molecules. Penicillin, discovered from Penicillium notatum, is discussed as a landmark achievement that changed human medicine. Cyclosporin A (used as an immunosuppressant) and statins (cholesterol-lowering drugs) are also produced using fungal sources — details that carry weight in board exams.
Sewage treatment is another important section. The chapter explains primary and secondary treatment of wastewater, where microbes break down organic matter. BOD (Biochemical Oxygen Demand) is a concept students must understand — it measures organic matter in water and is directly linked to pollution levels.
Biogas, Biocontrol Agents and Biofertilisers
The production of biogas — particularly methane — by methanogenic bacteria in biogas plants is covered in good detail. Students learn about the structure of biogas plants and how animal dung and organic waste are converted into usable fuel. This topic carries both environmental and economic significance and often appears in board and competitive exams.
The final sections deal with biocontrol agents (like Bacillus thuringiensis, which controls insect pests) and biofertilisers. Mycorrhiza, Rhizobium, and cyanobacteria like Anabaena are discussed as natural alternatives to chemical fertilisers. Understanding how these organisms fix nitrogen or improve phosphorus availability helps students connect microbiology with ecology and agriculture.
Key Topics Covered in Chapter 8
Role of Lactobacillus, yeast, and Aspergillus in food and industrial fermentation
Production of antibiotics — Penicillin from Penicillium notatum
Primary and secondary sewage treatment; BOD concept
Methane production through methanogenic bacteria in biogas plants
Bacillus thuringiensis (Bt) as a biocontrol agent for insects
Biofertilisers: Rhizobium, mycorrhiza, Anabaena, Nostoc
These NCERT solutions from Myclass24 cover all these points with clear, student-friendly language. Every solution is designed to help you score well in board exams and also build a strong conceptual foundation for NEET preparation.
NCERT Solutions for Class 12 Biology Chapter 8: Microbes in Human Welfare – FAQs
Microbes are microscopic organisms that include bacteria, fungi, viruses, and certain protozoans. Although some microbes cause diseases, many play a highly beneficial role in human life. They are used in food production, medicine, agriculture, waste management, and industrial processes. Microbes help prepare products such as curd, bread, and fermented foods, while some are used in the production of antibiotics and other useful substances. They also contribute to nutrient recycling in nature. Understanding the beneficial role of microbes helps students recognize their importance in improving human life, supporting industries, and maintaining environmental balance.
Microbes are widely used in the preparation of various food products and beverages through the process of fermentation. Certain bacteria help convert milk into curd, while yeast is commonly used in baking and the production of fermented beverages. During fermentation, microorganisms break down complex substances into simpler compounds, improving flavor, texture, and nutritional value. These microbial activities have been utilized by humans for centuries in food processing. Studying this application helps students understand the practical importance of microorganisms in daily life and highlights their contribution to the food industry and traditional food preparation methods.
Microbes have made significant contributions to medicine and healthcare. Certain microorganisms are used to produce antibiotics that help treat bacterial infections. Other microbes are involved in the production of vaccines, enzymes, and various pharmaceutical products. These biological products have improved disease prevention and treatment worldwide. Microorganisms are also used in scientific research to develop new medical technologies and therapies. Understanding the medical applications of microbes helps students appreciate how these tiny organisms contribute to improving human health and combating diseases. Their role in healthcare remains one of the most important achievements in modern biological science.