Class 12 Biology — Chapter 8: Microbes in Human Welfare
90 practice questions · 30 Easy · 30 Medium · 30 Hard
Practise Class 12 Biology Chapter 8, "Microbes in Human Welfare", with 90 NCERT-aligned multiple-choice questions. The set is split into 30 Easy, 30 Medium and 30 Hard questions, so you can warm up on the fundamentals and then push into the exam-level problems that separate top scorers in CBSE Board exams and NEET UG.
"Microbes in Human Welfare" is one of the chapters where diagram-based recall, terminology and NCERT line-by-line accuracy really pays off. Each MCQ on this chapter is timed and uses exam-grade marking (+2 correct, −1 wrong, 0 skipped), training the same accuracy-under-pressure that real papers demand. Every question carries a short explanation, so a wrong answer becomes a quick lesson rather than a dead end — the fastest way to close gaps before a test.
Use this chapter as targeted revision: attempt the Easy set first to confirm your basics on Microbes in Human Welfare, then move to Medium and Hard to test application and problem-solving. Your accuracy, streaks and XP save automatically, and the chapter feeds into your overall Class 12 Biology mastery score. A few sample questions are shown below; sign in free to practise all 90.
Key concepts: Microbes in Human Welfare (Class 12 Biology)
This chapter covers the useful roles of microbes — in food production, industrial products, sewage treatment, biogas, and as biofertilisers and biocontrol agents.
- Microbes in household food
- Lactobacillus curdles milk; yeast (Saccharomyces) ferments dough and beverages; microbes make cheese and other foods.
- Industrial products
- Microbes produce antibiotics (penicillin from Penicillium), organic acids, enzymes and alcoholic beverages by fermentation.
- Sewage treatment
- Microbes break down organic matter in primary and secondary (biological) treatment of waste water in STPs.
- Biogas
- Methanogens (e.g. Methanobacterium) in anaerobic conditions produce biogas (mainly methane) from organic waste/dung.
- Biofertilisers & biocontrol
- Rhizobium, mycorrhiza and cyanobacteria enrich soil; Bacillus thuringiensis and Trichoderma control pests and pathogens naturally.
💡 Exam tips for Microbes in Human Welfare
- Match the microbe to its product: Lactobacillus→curd, yeast→bread/alcohol, Penicillium→penicillin, Methanobacterium→biogas.
- Activated sludge in secondary sewage treatment relies on aerobic microbes — link BOD to water quality.
Sample questions
Curd from milk is produced by:
Lactic acid fermentation.
Activated sludge in sewage treatment is rich in:
Decompose organic matter.
Biogas (gobar gas) is mainly:
Methanogens produce CH₄.
Microbes in Human Welfare — FAQs
What are the key concepts in Class 12 Biology Microbes in Human Welfare?+
This chapter covers the useful roles of microbes — in food production, industrial products, sewage treatment, biogas, and as biofertilisers and biocontrol agents. Key ideas include Microbes in household food, Industrial products, Sewage treatment, Biogas, Biofertilisers & biocontrol.
What does Class 12 Biology Chapter 8 (Microbes in Human Welfare) cover on XamBaaz?+
It covers 90 NCERT-aligned MCQs on "Microbes in Human Welfare" — 30 Easy, 30 Medium and 30 Hard — each with a timed quiz and an instant explanation, suitable for CBSE Board exams and NEET UG.
Are these "Microbes in Human Welfare" questions free to practise?+
Yes — sign in with Google to practise "Microbes in Human Welfare" free. Full unlimited access is ₹999/year (limited-time launch price), with no per-chapter charges.
How should I revise "Microbes in Human Welfare" for the exam?+
Start with the Easy quiz to confirm your fundamentals, then attempt Medium and Hard for application-level practice. Review each explanation, retry the questions you miss, and track your accuracy on this chapter until it is consistently high.
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