This page collects frequently asked previous year questions from Microbes in Human Welfare across NEET, AIIMS and CBSE boards, with worked solutions. Context: microbes in food, industry, sewage treatment, biofertilisers and biocontrol.
Question 1 — NEET MCQ
“Which statement about microbes in human welfare is correct?”
Typical options test these four facts at once:
- Lactobacillus converts milk to curd and produces lactic acid.
- Saccharomyces cerevisiae is used in bread, beer and wine.
- Streptomyces produces streptomycin and many antibiotics.
- A deliberately wrong statement that mixes two of the above.
Usually one option contradicts a direct NCERT line. Strike it first.
Two will be subtly different versions of the same idea. Look for the unit or qualifier that separates them.
The correct answer matches the NCERT wording exactly. NEET rarely paraphrases — they quote.
Question 2 — Assertion and Reason
Assertion (A): Activated sludge process uses aerobic microbes to treat sewage.
Reason (R): A closely related textbook statement that may or may not explain the assertion.
Is the assertion true on its own? Verify against NCERT.
Is the reason a correct statement on its own?
This is the trick — both can be true without R being the reason for A.
Classic NEET pattern: both A and R are true, but R is not the correct explanation of A. Always check the explanation link separately.
Question 3 — match the columns
Column I lists structures or processes; Column II lists functions. A typical microbes in human welfare question has four or five pairs.
Usually two out of four are obvious. Lock those in and eliminate from the other column.
Even if you are unsure about the last pair, you can deduce it by exclusion.
Full marks come from method — never leave a match column blank, fill the last entry by exclusion.
Question 4 — CBSE short answer (3 marks)
“Explain the working of microbes in human welfare with a labelled diagram.”
A three-mark answer wants:
- 1 mark for a labelled diagram.
- 1 mark for the function statement.
- 1 mark for a mechanism sentence.
Model answer skeleton:
Microbes in Human Welfare is responsible for microbes in food, industry, sewage treatment, biofertilisers and biocontrol. The key steps are: first, the input is processed; second, the intermediates form; third, the output is produced. Relevant numerical value: Lactobacillus converts milk to curd and produces lactic acid.
CBSE rewards crisp 3-line answers for 3 marks. Do not write an essay — you lose time and gain nothing.
Question 5 — CBSE long answer (5 marks)
A 5-mark question usually has two parts: describe the structure, then explain a disorder or application. Allocate 3 + 2 marks.
Aim for crisp diagrams over long prose. Examiners award marks for labels and sequence, not for adjectives.
For Microbes in Human Welfare, the repeat rate of PYQ concepts is high — around 40% of NEET questions recycle an older idea. Practise the last 10 years before touching new material.