Chapter 9 of 10
Syllabus
Microbes in Human Welfare — Syllabus
Tamil Nadu Board · Class 12 · Zoology
What Microbes in Human Welfare covers in Tamil Nadu Board Class 12 Zoology: 4 topics, for the 2026-27 session.
45 questions25 flashcards5 concepts
Interactive on Super Tutor
Studying Microbes in Human Welfare? Get the full interactive chapter.
Quizzes, flashcards, AI doubt-solver and a step-by-step study plan — built for syllabus and more.
Free trial, no card needed.
4 Topics · Tamil Nadu Board Class 12 Zoology · 2026-27
Topics in Microbes in Human Welfare
1
9.1 Microbes in Household Products
- Lactic Acid Bacteria (LAB) including Lactobacillus acidophilus, L. lactis, and Streptococcus lactis are probiotics that prevent pathogenic microbial growth in the digestive tract
- Probiotics are live microorganisms providing health benefits by improving gut flora, while prebiotics are food compounds that induce the growth of beneficial microorganisms
- Curd production involves LAB converting milk protein casein into lactic acid and other organic acids, making curd more nutritious than milk
2
9.2 Microbes in Industrial Products
- Fermentors (bioreactors) are closed vessels with controlled aeration, agitation, temperature, pH, and waste removal systems for large-scale microbial cultivation
- Penicillin, discovered by Alexander Fleming in 1926, was the first antibiotic produced by Penicillium notatum and P. chrysogenum fungi
- Fleming, Chain, and Florey received the 1945 Nobel Prize for penicillin discovery; penicillin is called the 'queen of drugs' and is bactericidal (kills bacteria)
3
9.3 Microbes in Sewage Treatment and Energy Generation
- Sewage is waste generated daily in cities and towns containing human excreta, organic matter, and pathogenic microbes
- Domestic waste comprises approximately 99% water, suspended solids, and soluble organic and inorganic substances
- Sewage treatment must occur before discharge into natural water bodies like rivers and streams to prevent pollution
4
9.4 Microbes in the Production of Biogas
- Biogas is a mixture of gases produced by breakdown of organic matter in absence of oxygen (anaerobic digestion)
- Biogas can be produced from agricultural wastes, manure, municipal wastes, plant material, sewage, and food waste
- Biogas composition: methane (63%), CO₂, and hydrogen; devoid of smell and burns with blue flame without smoke
Key Concepts
Probiotics are live beneficial microorganisms (likeLactobacillus species convert milk protein (casein)Cheese is produced by coagulationBread dough is fermented by SaccharomycesEdible unicellular microorganisms like Spirulina can
Work through every topic in Microbes in Human Welfare with notes and quizzes
Start This ChapterFrequently Asked Questions
What are the important topics in Microbes in Human Welfare for Tamil Nadu Board Class 12 Zoology?
Key topics in Microbes in Human Welfare include 1 Microbes in Household Products, 2 Microbes in Industrial Products, 3 Microbes in Sewage Treatment and Energy Generation, 4 Microbes in the Production of Biogas. Study these first, then practise questions on each for the Tamil Nadu Board Class 12 board exam.
How should I revise Microbes in Human Welfare for the Tamil Nadu Board Class 12 board exam?
Learn the core ideas first, then work through the 45 practice questions on Microbes in Human Welfare. Revise definitions regularly and use flashcards for quick recall before the exam.
Sources & Official References
Content is aligned to the official syllabus. Refer to the board website for the latest curriculum.
More resources for Microbes in Human Welfare
For serious students
Get the full Microbes in Human Welfare chapter — start free.
Quizzes, flashcards, an AI doubt solver and a study plan for Tamil Nadu Board Class 12 Zoology. Free to start, no card needed.