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Microbes in Human Welfare

Tamil Nadu Board · Class 12 · Zoology

Complete topic list for Microbes in Human Welfare in Tamil Nadu Board Class 12 Zoology. Key concepts, sub-topics, and what to focus on for board exams.

45 questions25 flashcards5 concepts

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4 Topics · Tamil Nadu Board Class 12 Zoology

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

Frequently 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 Microbes in Human Welfare — Chapter Overview, Mind map showing major categories of microbial applications in human welfare, including household products, industrial manufacturing, sewage treatment, energy generation, and environmental remediation, Flowchart distinguishing between probiotics (live beneficial organisms) and prebiotics (fibers that support them), showing how both contribute to gut health and disease prevention. These are the concepts Tamil Nadu Board Class 12 examiners draw on most — study them first, then practise related questions.
How to score full marks in Microbes in Human Welfare — Tamil Nadu Board Class 12 Zoology?
Understand the core concepts first, then work through the 45 practice questions available for this chapter. Revise formulas and 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.

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