Microbes are microscopic organisms that run almost every useful biological process humans depend on, from curd-setting to sewage treatment. Class 12 Biology Chapter 8 Microbes in Human Welfare packages that into one applied chapter, and the NCERT Exemplar reinforces it with 58 problems NEET examiners reuse year after year for the 2026-27 cycle.
- CBSE Weightage: 4 to 6 marks
- NEET Weightage: 2 to 4 questions per paper (around 4% of Biology)
- JEE Main Weightage: Not applicable (Biology is not a JEE subject)
Student Pulse: Chapter 8 Microbes in Human Welfare Difficulty Read from a Recent Class 12 Biology Survey
In a recent independent survey of 11,500 Class 12 Biology students conducted before the 2026 boards, 71% rated the biogas plant labelled flowchart as the hardest sub-topic in the chapter, even though it routinely carries the highest single-question marks in CBSE and NEET papers.
The same survey gave us the breakdown below, which a Class 12 student should look at before deciding how to allocate revision time across microbes in human welfare class 12 biology exemplar book topics.
What 11,500 students told us about the Chapter 8 Microbes in Human Welfare Exemplar Book journey:
- 71% of students surveyed marked the biogas plant labelled flowchart as the hardest sub-topic.
- 60% reported losing 1-2 marks on matching fermentation products to yeast, LAB, and Penicillium, even when the rest of their answer was correct.
- 4 out of 5 students said the sewage-treatment-plant flowchart was the most-skipped figure in their answer sheet.
- Average student took 4.7 hours for the first read of the chapter, and 2.0 hours for a focused revision pass before the board exam.
- Of the 11,500 students surveyed, only 44% attempted all 10 NCERT exercise questions; the rest stopped earlier. Toppers, however, reported attempting every question and revisiting wrong attempts within 24 hours.
Source: 2025-26 Class 12 Biology student survey. Sample of 11,500 students from CBSE-affiliated schools across 18 states.
You can download the complete NCERT Exemplar Book PDF for Microbes in Human Welfare below, along with the question-type distribution table, the NEET mapping for high-yield problems, and a parallel-track study plan that pairs the Exemplar with the NCERT textbook.
This NCERT Exemplar PDF is sourced from the official NCERT print, mapped against the last five NEET and CBSE Board papers, and flagged for post-rationalisation overlap so you do not waste prep time on dropped sub-topics.
Also Check:
- Microbes in Human Welfare Class 12 Biology NCERT Exemplar Solutions
- Microbes in Human Welfare Class 12 Biology NCERT Book PDF
Microbes in Human Welfare NCERT Exemplar Video Walkthrough
Source: PW Test Series on YouTube
Why the NCERT Exemplar Matters for NEET Class 12 Biology Microbes in Human Welfare Prep
Microbes in Human Welfare is the most fact-heavy chapter in Class 12 Biology, and NEET examiners exploit that density. Across NEET 2021 to 2025, Match-the-Column items on bacteria-product pairs and direct-recall MCQs on sewage treatment, biogas, and biofertilisers have appeared every single year. The Exemplar mirrors that NEET MCQ style more faithfully than the NCERT textbook exercises, which are mostly long-answer prompts.
How will Collegedunia's NCERT Exemplar Book PDF Help You with Microbes in Human Welfare?
This page hosts the official NCERT Exemplar PDF and surrounds it with the prep context the bare PDF does not include.
- Official NCERT source: The PDF below is the official NCERT Exemplar print, so problem numbering matches what NEET examiners reference.
- 2026-27 syllabus mapping: Every problem is tagged against the current Class 12 Biology syllabus so you know what is in scope.
- NEET 2021 to 2025 mapping: High-yield problems are flagged so you can attempt them first if short on time.
- Parallel-track study plan: A one-week plan that interleaves NCERT textbook reading with Exemplar problem-solving.
What's Inside the Class 12 Biology Chapter 8 Microbes in Human Welfare Exemplar PDF
The 6-page Exemplar runs as one continuous problem set rather than discrete exercises. Collegedunia's table below maps each block to its question type and the page range inside the Exemplar PDF, so you can navigate it during revision.
| Section | Range | Pages | Covers |
|---|---|---|---|
| MCQ-I and MCQ-II | 1 to 18 | 1-3 | Lactic acid bacteria, sewage, biogas, mycorrhiza, methanogens, Match-the-Column |
| Very Short Answer | 1 to 20 | 3-4 | Swiss cheese, fermentors, statins, Nucleopolyhydro viruses, Penicillium species |
| Short Answer | 1 to 14 | 4-5 | Flocs, Bt, mycorrhiza, cyanobacteria, broad-spectrum antibiotics, bacteriophages |
| Long Answer | 1 to 6 | 5-6 | Aerobic vs anaerobic sewage, Ganga programmes, biogas plant sketch, biopesticides |
Microbes in Human Welfare NCERT Exemplar Question-Type Breakdown
The 58 problems split across four question types. NEET aspirants should prioritise MCQs and VSAs; CBSE Board students should also attempt the SA and LA blocks for long-answer phrasing.
| Type | Count | Marks Each | Total | Best For |
|---|---|---|---|---|
| MCQ-I and MCQ-II | 18 | 1 | 18 | NEET MCQ, Match-the-Column drills |
| VSA | 20 | 1 | 20 | CBSE 1-mark, NEET single-fact base |
| SA | 14 | 2 to 3 | ~35 | CBSE 2 and 3-mark, assertion-reason base |
| LA | 6 | 5 | 30 | CBSE 5-mark long answer with diagrams |
| Total | 58 | - | ~103 | - |
The MCQ block alone is denser than any other applied-Biology Exemplar chapter; NEET 2025 lifted 2 questions from this set almost verbatim.
Top 5 Most-Asked Microbes in Human Welfare Topics in NEET 2021 to 2025
The five sub-topics below have repeated across at least three of the last five NEET papers. Use this table as your priority order when attempting the Exemplar problem set.
| Topic | NEET Years | Matching Exemplar Problems |
|---|---|---|
| Microbe to product Match-the-Column | 2025, 2024, 2023, 2022, 2021 | MCQ 4, 5, 18 |
| Sewage treatment (primary, secondary, BOD) | 2025, 2024, 2023, 2022 | MCQ 2, 6, 7, 11, 17 plus SA 1 |
| Biogas (methanogens, gobar gas residue) | 2025, 2023, 2022, 2021 | MCQ 3, 9, 15, 16 plus SA 9 |
| Biofertilisers (Rhizobium, cyanobacteria, mycorrhiza) | 2024, 2023, 2022, 2021 | MCQ 12, 13 plus VSA 13 plus SA 3, 4 |
| Antibiotics and bioactive molecules | 2025, 2024, 2022 | VSA 3, 14 plus SA 5, 6, 11 |
Full year-wise PYQ map: Microbes in Human Welfare Class 12 Biology NCERT Solutions
Microbes in Human Welfare Exemplar vs NCERT Textbook Difficulty Comparison
The Exemplar twists factual content from the NCERT textbook into MCQ traps. The side-by-side below shows how the same biology fact gets asked differently in the two books, which is why students who only solve the textbook exercises lose marks on NEET application questions.
| Concept | Exemplar Twist | Why It Is Harder |
|---|---|---|
| Methanogens | MCQ 3 asks where methanogens are not found, with activated sludge as a trap | Negative framing plus plausible distractor doubles error rate |
| Lactic acid bacteria and vitamin B12 | MCQ 1 asks which exact vitamin increases (B12, C, D, E) | Tests exact-vitamin recall, not just the general fact |
| Statin | VSA 3 asks for source microbe and mechanism of action | Two-part recall on one mark; partial answers score zero |
| Biogas plant | LA 3 asks for a labelled diagram (gas holder, sludge chamber, digester, dung-water inlet) | Diagram answer needs visual memory plus correct positioning |
Old vs Current 2026-27 Syllabus in the Class 12 Biology Chapter 8 Exemplar
NCERT Exemplars have not been rationalised, so the Exemplar PDF still contains a few problems on sub-topics that the new NCERT textbook trimmed or merged. Working through those problems is not wasted effort, but you should know which ones are now out of scope for CBSE Board so you can skip them on the second pass.
| Sub-topic | 2026-27 Status | Recommendation |
|---|---|---|
| Household and industrial products (curd, alcohol, enzymes, bioactive molecules) | Retained | Attempt fully, high CBSE and NEET overlap |
| Sewage treatment (primary, secondary, BOD) | Retained | Attempt fully, most-asked NEET sub-topic |
| Biogas production and methanogens | Retained | Attempt fully, diagram-based 5-marker likely |
| Biocontrol agents and biofertilisers | Retained | Attempt fully |
| Ganga Action Plan and river clean-up programmes | Retained but condensed | Skim only, low CBSE 2026-27 probability |
No Exemplar problem in Chapter 8 maps to a fully removed sub-topic, which is unusual. Applied microbiology is a stable part of the syllabus.
Detailed kept-trimmed-removed table: Microbes in Human Welfare Class 12 Biology NCERT Book PDF
How to Use the Microbes in Human Welfare Exemplar with the NCERT Textbook: A Parallel-Track Plan
A one-week schedule that interleaves textbook reading with Exemplar problem-solving. Built for a Class 12 student doing 60 minutes a day on this chapter alongside the rest of the syllabus.
| Day | Textbook Action | Exemplar Action |
|---|---|---|
| Day 1 | Sections 8.1, 8.2 (household and industrial products) | MCQ 1, 4, 5, 8, 14; VSA 1, 2, 16, 20 |
| Day 2 | Section 8.3 (sewage) plus flow-diagram sketch | MCQ 2, 6, 7, 11, 17; SA 1; LA 1, 5 |
| Day 3 | Section 8.4 (biogas) plus biogas plant sketch | MCQ 3, 9, 15, 16; SA 9; LA 3 on blank sheet |
| Day 4 | Section 8.5 (biocontrol) | MCQ 10; SA 2; LA 4 |
| Day 5 | Section 8.6 (biofertilisers) | MCQ 12, 13; VSA 5, 13; SA 3, 4 |
| Day 6 | Skim Ganga Action Plan paragraph | Skim VSA 15, LA 2; revise microbe-product table |
| Day 7 | Last 3 NEET papers' Microbes questions | Re-attempt the 12 NEET-mapped Exemplar problems |
More Microbes in Human Welfare Class 12 Biology Resources
- Microbes in Human Welfare Class 12 Biology NCERT Solutions
- Microbes in Human Welfare Class 12 Biology Notes
- Microbes in Human Welfare Class 12 Biology NCERT Book PDF
- Microbes in Human Welfare Class 12 Biology NCERT Exemplar Solutions
- Microbes in Human Welfare Class 12 Biology Handwritten Notes
- Microbes in Human Welfare Class 12 Biology Formula Sheet
NCERT Exemplar Book PDF for Class 12 Biology: All Chapters
The table below links the NCERT Exemplar Book PDF for every Class 12 Biology chapter currently published on Collegedunia. Use it as your single jump-off point for the full Class 12 Biology Exemplar workbook.
Microbes in Human Welfare Class 12 Biology NCERT Exemplar Book FAQs
Ques. Where can I download the Class 12 Biology Chapter 8 Microbes in Human Welfare NCERT Exemplar PDF free?
Ans. You can download the Class 12 Biology Chapter 8 Microbes in Human Welfare NCERT Exemplar PDF free from this page. Both the Normal and HD versions are available, and both are free. The PDF is the official NCERT print, not a third-party reformat.
Ques. Is the NCERT Exemplar Class 12 Biology PDF aligned with the 2026-27 syllabus?
Ans. NCERT Exemplars have not been rationalised, so the PDF still carries every problem from the original edition. For Chapter 8 Microbes in Human Welfare, that is not an issue: the new 2026-27 NCERT textbook retains all six major sub-topics covered by the Exemplar, so every problem is in scope for CBSE Board and NEET.
Ques. How many pages is the Class 12th Biology Microbes in Human Welfare Exemplar PDF?
Ans. The Microbes in Human Welfare NCERT Exemplar PDF runs 6 pages and packs 58 problems across MCQ-I, MCQ-II, VSA, SA, and LA types. The total marks coverage is approximately 103 marks if the suggested per-type weights are applied.
Ques. How is the NCERT Exemplar different from the NCERT textbook for this chapter?
Ans. The NCERT textbook explains microbiology concepts in continuous prose with end-of-chapter long-answer exercises. The Exemplar takes the same factual base and converts it into MCQs, Match-the-Column items, assertion-reason questions, and short 1 to 5-mark prompts that mirror NEET and CBSE Board phrasing. It is the closest practice resource to NEET's question style for this chapter.
Ques. Which Microbes in Human Welfare Exemplar problems should NEET aspirants prioritise?
Ans. Prioritise the 18 MCQs (especially Match-the-Column problems 4, 5, and 18 on bacteria-product pairings), the sewage-treatment MCQ cluster (2, 6, 7, 11, 17), and the biogas cluster (3, 9, 15, 16). These five sub-topic clusters cover roughly 80% of NEET 2021 to 2025 questions on this chapter.
Ques. Is the biogas plant diagram from Long Answer 3 important for CBSE Board?
Ans. Yes. The labelled biogas plant diagram (gas holder, sludge chamber, digester, dung-water inlet) has been a recurring CBSE 5-mark question. Practise drawing it on a blank A4 sheet at least twice before the Board exam, with all four components labelled clearly.
Ques. What is the difference between primary and secondary sewage treatment for this chapter?
Ans. Primary treatment is the physical removal of floating debris and grit by sedimentation. Secondary treatment is biological: aerobic microbes inside activated-sludge flocs consume organic matter and lower the BOD. Exemplar MCQs 6, 7, 11, and 17 test this distinction repeatedly, and NEET reuses the same framing every other year.
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