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NEET ZoologyUpdated 19 Oct 2026

Microbes in Human Welfare: NEET PYQs and weightage

Microbes in Human Welfare carries 3.9 of 100 Zoology marks in NEET by past-paper share: 25 of the 648 tagged NEET Zoology PYQs in the ViJEEta bank (NEET 2013–2026). It ranks 14 of 17 Zoology chapters.

Take the 25-question Microbes in Human Welfare testKey facts ↓All NEET Zoology chapters
3.9/100 Weight in Zoology
3 of 5 Exam importance (3/5, by past-paper share)
25 NEET PYQs
287 Practice questions
268 With measured difficulty

How the weight is computed: this chapter's tagged NEET PYQs divided by all tagged NEET Zoology PYQs in the bank (25 of 648), times 100, with repeated questions counted once. The bank does not store the year of each NEET question, so none is printed. Computed from the bank at build time. Updated 19 Oct 2026.

Microbes in Human Welfare: key facts for NEET

16 facts the paper keeps asking, each with how it is asked. Copy it onto one page of your notebook: that page is this chapter's handbook.

  1. Lactic acid bacteria and curd

    Lactobacillus and other lactic acid bacteria (LAB) turn milk into curd; their acids coagulate and partly digest milk proteins, and curd gains vitamin .

    Asked as: Which vitamin increases when milk is converted to curd by LAB?

  2. Dough fermentation

    Bread dough is fermented by baker's yeast, Saccharomyces cerevisiae; dosa and idli dough is fermented by bacteria; makes the dough puff up.

    Asked as: Match the food with the microbe that ferments it: bread, idli dough, curd.

  3. Toddy

    Toddy, a traditional South Indian drink, comes from fermenting palm sap.

    Asked as: Toddy is made by fermenting the sap of which plant?

  4. Cheese

    Swiss cheese gets its large holes from the made by Propionibacterium sharmanii; Roquefort cheese is ripened by growing a fungus on it.

    Asked as: The large holes in Swiss cheese are due to which bacterium?

  5. Alcoholic beverages

    Brewer's yeast (S. cerevisiae) ferments malted cereals and fruit juices to ethanol; wine and beer are not distilled, but whisky, brandy and rum are.

    Asked as: Which of these alcoholic drinks is produced without distillation?

  6. Penicillin

    Penicillin was the first antibiotic, found by chance by Alexander Fleming in Penicillium notatum while he worked on Staphylococci; Chain and Florey later established its full potential, and all three won the Nobel Prize in 1945.

    Asked as: Who established penicillin's potential as an effective antibiotic?

  7. Organic acid producers

    Acid producers: Aspergillus niger (fungus) makes citric acid, Acetobacter aceti makes acetic acid, Clostridium butylicum makes butyric acid, Lactobacillus makes lactic acid.

    Asked as: Match each organism with the organic acid it produces (and say whether it is a bacterium or a fungus).

  8. Industrial enzymes

    Lipases are used in detergents to remove oily stains; pectinases and proteases are used to clarify bottled fruit juices.

    Asked as: Which enzymes are used to clarify bottled fruit juice?

  9. Streptokinase

    Streptokinase comes from Streptococcus and is modified by genetic engineering; it is used as a 'clot buster' for patients with myocardial infarction.

    Asked as: Which bacterium is the source of the clot buster streptokinase?

  10. Cyclosporin A and statins

    Cyclosporin A, an immunosuppressant for organ-transplant patients, comes from the fungus Trichoderma polysporum; statins come from the yeast Monascus purpureus and lower blood cholesterol by competitively inhibiting the enzyme that synthesises it.

    Asked as: Match the bioactive molecule with its source organism and its use.

  11. Primary and secondary sewage treatment

    Primary sewage treatment is physical (filtration, then sedimentation): settled solids form the primary sludge and the supernatant forms the effluent. Secondary treatment is biological: aerobic microbes in aeration tanks grow into flocs and reduce the BOD.

    Asked as: What is the key difference between primary and secondary sewage treatment?

  12. BOD

    BOD is the oxygen that bacteria would consume to oxidise all the organic matter in of water; the higher the BOD, the more polluting the water.

    Asked as: Assign BOD values to untreated sewage, river water and secondary effluent; which is the most polluted?

  13. Activated sludge and biogas

    Settled flocs form activated sludge: a small part goes back to the aeration tank as inoculum, and most goes to anaerobic sludge digesters, where the gases produced (methane, , ) form biogas.

    Asked as: Where is part of the activated sludge sent back to, and why?

  14. Methanogens

    Methanogens such as Methanobacterium grow anaerobically on cellulosic material and are found in anaerobic sludge and in the rumen of cattle; biogas technology in India came mainly from IARI and KVIC.

    Asked as: Which bacterium produces biogas, and where does it occur naturally?

  15. Biocontrol agents

    Bacillus thuringiensis (Bt) kills butterfly caterpillars, Trichoderma is a free-living fungal biocontrol agent of plant pathogens, and Nucleopolyhedrovirus (a baculovirus) is a narrow-spectrum insecticide suited to IPM.

    Asked as: Match each biocontrol agent with its target or type.

  16. Biofertilisers

    Biofertilisers: Rhizobium fixes nitrogen symbiotically in root nodules; Azospirillum and Azotobacter fix it while free-living; Glomus forms mycorrhiza and absorbs phosphorus for the plant; Anabaena, Nostoc and Oscillatoria are cyanobacteria used in paddy fields.

    Asked as: Which biofertiliser is symbiotic and which is free-living? What does mycorrhiza supply to the plant?

Trap

Trichoderma polysporum (a fungus) makes cyclosporin A, but Monascus purpureus (a yeast) makes statins. Also, the Trichoderma used in biocontrol is a different role of the same genus. Don't swap them.

How does NEET ask Microbes in Human Welfare?

8 real previous-year questions from this chapter, as printed in the paper, each with its worked solution. Answer the first one here with no sign-in.

Q1ZoologyNEET UG PYQMicrobes in Industrial Products
Try right here · No sign-in
Which of the following is wrongly matched in the given table?
Answer key (D) & worked solution

Correct answer: Option D

Cyclosporin A and C are immunosuppressive drugs that are obtained from Trichoderma polysporum. Statins produced by the yeast Monascus purpureus is used as the blood-cholesterol-lowering agent. It acts by competitively inhibiting the enzyme responsible for the synthesis of cholesterol. Streptokinase is an enzyme secreted by several species of Streptococci that can bind and activate human plasminogen. It is used as an effective thrombolysis medication. Clostridium butylicum is used for the production of butyric acid. It has a wide range of applications such as paints, coatings, etc.
Q2ZoologyNEET UG PYQMicrobes in Industrial Products
Match List I with List II: List I (Bioactive molecules)List II (Importance)A.StreptokinaseI.Immunosuppressive agentB.StatinsII.Removal of clots from the blood vesselsC.LipasesIII.Blood cholesterol-lowering agentD.Cyclosporin AIV.Detergent formulations Choose the correct answer from the options given below:
AA–II, B–III, C–IV, D–I
BA–IV, B–III, C–II, D–I
CA–II, B–III, C–I, D–IV
DA–III, B–II, C–IV, D–I
Answer key (A) & worked solution

Correct answer: Option A

Streptokinase → Used as 'clot buster' for removing clots from the blood vessels Statins → Blood cholesterol lowering agent, produced by Monascus purpureus Lipases → Used in detergent formulation Cyclosporin A → Used as immunosuppressive agent in organ transplant patients and produced by Trichoderma polysporum
Q3ZoologyNEET UG PYQMicrobes in Industrial Products
Match the following list of microbes and their importance. (a)Saccharomyces cerevisiae(i)Production of immunosuppressive agents(b)Monascus purpureus(ii)Ripening of Swiss cheese(c)Trichoderma polysporum(iii)Commercial production of ethanol(d)Propionibacterium sharmanii(iv)Production of blood cholesterol-lowering agents
A(a)-(iii); (b)-(iv); (c)-(i); (d)-(ii)
B(a)-(iv); (b)-(iii); (c)-(ii); (d)-(i)
C(a)-(iv); (b)-(ii); (c)-(i); (d)-(iii)
D(a)-(iii); (b)-(i); (c)-(iv); (d)-(ii)
Answer key (A) & worked solution

Correct answer: Option A

a. Saccharomyces cerevisiae is used for the commercial production of ethanol. b. Monascus purpureus has been commercialised as a blood-cholesterol lowering agent. c. Trichoderma polysporum is used for the production of immunosuppressive agents. d. Propionibacterium sharmanii is used for the ripening of Swiss cheese.
Q4ZoologyNEET UG PYQMicrobes in Industrial Products
Which of the following is correctly matched for the product produced by them?
APenicillium notatum: Acetic acid
BSaccharomyces cerevisiae: Ethanol
CAcetobacter aceti: Antibiotics
DMethanobacterium: Lactic acid
Answer key (B) & worked solution

Correct answer: Option B

Saccharomyces cerevisiae is commonly called Brewer’s yeast. It causes the fermentation of carbohydrates producing ethanol. Ethanol fermentation can be defined as a biological process in which glucose is converted into ethanol followed by the release of carbon dioxide.
Q5ZoologyNEET UG PYQMicrobes as Biofertilizers
Mycorrhizae are the example of
AAntibiosis
BMutualism
CFungistasis
DAmensalism
Answer key (B) & worked solution

Correct answer: Option B

Mycorrhizae is a mutualistic association of fungi with roots of higher plants. Mutualism can be defined as the association in which both the involved organisms are benefited. In a mycorrhizal association, the fungi colonize the root system of the host plant providing increased water and mineral absorption capabilities. While the plant provides the fungus with carbohydrates formed from photosynthesis.
Q6ZoologyNEET UG PYQMicrobes in Sewage Treatment
What gases are produced in anaerobic sludge digesters?
AMethane, hydrogen sulphide and CO
BMethane, hydrogen sulphide and O
CHydrogen sulphide and CO
DMethane and CO only
Answer key (A) & worked solution

Correct answer: Option A

In anaerobic sludge digesters, other kinds of bacteria which grow anaerobically, digest the bacteria and the fungi in the sludge and produce a mixture of gases such as methane, hydrogen sulphide and carbon dioxide.These gases are produced during biogas production by the activity of bacteria called methanogens.
Q7ZoologyNEET UG PYQMicrobes in Industrial Products
A good producer of citric acid is
AAspergillus
BPseudomonas
CClostridium
DSaccharomyces
Answer key (A) & worked solution

Correct answer: Option A

Aspergillus niger is used for the production of citric acid.
Q8ZoologyNEET UG PYQMicrobes in Household Products
Which of the following microbes is NOT. involved in the preparation of household products? A. Aspergillus niger B. Lactobacillus C. Trichoderma polysporum D. Saccharomyces cerevisiae E. Propionibacterium sharmanii Choose the correct answer from the options given below:
AC and D only
BC and E only
CA and B only
DA and C only
Answer key (D) & worked solution

Correct answer: Option D

Aspergillus niger and Trichoderma polysporum are not involved in preparation of household products.

Which topics in Microbes in Human Welfare carry the most questions?

All 7 topics, by tagged PYQs, then practice questions. Counted from the bank. Updated 19 Oct 2026.

TopicPYQsPractice questions
Microbes in Industrial Products1480
Microbes in Household Products453
Microbes in Sewage Treatment448
Microbes as Biocontrol Agents231
Microbes as Biofertilizers139
Microbes in Production of Biogas026
Miscellaneous Examples010

Why does Microbes in Human Welfare show "–" until you answer 3 questions?

Unknown is not zero. Until you answer at least 3 graded questions in Microbes in Human Welfare, ViJEEta shows – instead of a zero or a 50% default. Book exercises can raise chapter mastery up to 0.60, adaptive practice up to 0.75, and only a timed chapter test or mock can certify 0.80 and above.

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What happens when you test Microbes in Human Welfare?

Every chapter test is 25 questions. It starts at moderate difficulty and adapts after each saved answer. If you open a solution before answering, that attempt earns no credit, so your mastery stays honest.

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Chapters either side of Microbes in Human Welfare by weight

Structural Organisation in Animals Weight 4.6/100Biotechnology and Its Applications Weight 4.5/100Digestion and Absorption Weight 3.4/100Neural Control and Coordination Weight 3.2/100