Microbes in Human Welfare is one of the most scoring and NCERT-based chapters in NEET Biology. Questions from this unit are often direct, factual, and repeated with slight variations. If you want to secure easy marks, mastering the Top 5 Microbes Questions is a must.
This chapter covers microbes in household products, industrial production, sewage treatment, biogas, and biocontrol. In this article, we will break down the Microbes Questions with detailed explanations, tricks, and NCERT-backed concepts to help you revise efficiently and score high.
Why Focus on Top 5 Microbes Questions?
The Top 5 Microbes Questions are extremely important because:
- Most questions are directly lifted from NCERT lines
- High probability of repetition in NEET
- Conceptual + factual combination makes it scoring
- Easy to revise in a short time
The Microbes Questions mainly focus on microbes used in industry, food production, sewage treatment, and antibiotics.

Question 1: Microbes in Household Products
Question:
Which microorganism is used in the production of curd?
Options:
A. Saccharomyces cerevisiae
B. Lactobacillus
C. Aspergillus
D. Penicillium
Answer: B. Lactobacillus
Explanation:
Lactobacillus bacteria convert lactose into lactic acid, which coagulates milk proteins to form curd. It also improves nutritional quality by increasing vitamin B12.
This is one of the most repeated questions in the Microbes Questions, often asked directly from NCERT.
Trick:
Remember: “Lacto = Milk → Lactobacillus = Curd”
Question 2: Microbes in Industrial Production
Question:
Which microorganism is used for commercial production of ethanol?
Options:
A. Lactobacillus
B. Saccharomyces cerevisiae
C. Clostridium
D. Rhizobium
Answer: B. Saccharomyces cerevisiae
Explanation:
Saccharomyces cerevisiae (yeast) is used in fermentation to convert sugars into ethanol and carbon dioxide. It is widely used in baking and brewing industries.
Industrial applications are frequently tested in the Microbes Questions, especially ethanol and antibiotics.
Trick:
“Yeast = Fermentation = Alcohol”
Question 3: Antibiotic Production
Question:
Penicillin is obtained from:
Options:
A. Bacteria
B. Virus
C. Fungus
D. Algae
Answer: C. Fungus
Explanation:
Penicillin is produced by the fungus Penicillium. It was discovered by Alexander Fleming and is one of the first antibiotics used to treat bacterial infections.
This is a classic and repeatedly asked concept in the Microbes Questions.
Trick:
“Penicillium → Penicillin”
Question 4: Sewage Treatment Process
Question:
The flocs formed during secondary sewage treatment consist of:
Options:
A. Dead organic matter
B. Fungal hyphae
C. Microbial biomass
D. Inorganic particles
Answer: C. Microbial biomass
Explanation:
During secondary treatment, aerobic microbes form flocs (clusters) that consume organic matter. These flocs are then used to reduce pollution load.
Sewage treatment is a very important topic in the Microbes Questions, often asked in sequence-based or concept-based questions.
Trick:
“Flocs = Microbes eating waste”
Question 5: Biogas Production
Question:
Biogas is mainly composed of:
Options:
A. Oxygen
B. Methane
C. Nitrogen
D. Hydrogen
Answer: B. Methane
Explanation:
Biogas is produced by methanogens (like Methanobacterium) under anaerobic conditions. It mainly consists of methane, which is used as fuel.
Biogas and methanogens are frequently tested in the Microbes Questions, especially from NCERT diagrams.
Trick:
“Biogas = Methane = Energy”
Important Concepts Behind Top 5 Microbes Questions
To master the Microbes Questions, you must have strong clarity on the following NCERT concepts:
Microbes in Household Products
Microorganisms like Lactobacillus are used in curd formation, while yeast is used in baking. These examples are directly asked in the Microbes Questions.
Microbes in Industrial Products
Microbes are used to produce:
- Ethanol (yeast)
- Antibiotics (Penicillium, Streptomyces)
- Organic acids (Aspergillus)
Understanding microbe-product relationships is crucial for solving the Top 5 Microbes Questions.
Sewage Treatment
Sewage treatment occurs in two stages:
- Primary treatment: Physical removal
- Secondary treatment: Biological treatment using microbes
Flocs and activated sludge are key terms frequently appearing in the Top 5 Microbes Questions.
Biogas Production
Methanogens produce methane from organic waste under anaerobic conditions. Gobar gas plants are a common example.
This is a direct NCERT-based concept often asked in the Top 5 Microbes Questions.
Microbes as Biocontrol Agents
Microbes like Bacillus thuringiensis (Bt) are used as biopesticides. They help in pest control without harming the environment.
Biocontrol is an important and often overlooked topic in the Top 5 Microbes Questions.
Common Mistakes Students Make
While preparing the Top 5 Microbes Questions, students often:
- Confuse microbes with their products
- Forget names of organisms (like Saccharomyces)
- Mix up sewage treatment stages
- Ignore NCERT examples and diagrams
Avoiding these mistakes can significantly improve your accuracy.
Tips to Master Top 5 Microbes Questions
To excel in the Top 5 Microbes Questions, follow these strategies:
- Read NCERT line by line (especially examples)
- Memorize microbe-product pairs
- Practice PYQs regularly
- Revise diagrams of sewage treatment and biogas plant
- Use mnemonics and tricks
Consistency and revision are key to mastering the Top 5 Microbes Questions.
Conclusion
The Top 5 Microbes Questions are among the easiest scoring areas in NEET Biology if prepared properly. Since most questions are directly based on NCERT, a strong focus on examples, processes, and microbial applications can give you an edge. By mastering these repeated PYQs and using the provided tricks, you can significantly improve your accuracy and confidence.
FAQs on Top 5 Microbes Questions
1. How important are Top 5 Microbes Questions for NEET?
The Top 5 Microbes Questions are very important as they cover frequently repeated and NCERT-based concepts.
2. Which topics are most important in this chapter?
Key topics include household products, industrial microbes, sewage treatment, biogas, and biocontrol—all part of the Top 5 Microbes Questions.
3. Is NCERT enough for Microbes in Human Welfare?
Yes, most Top 5 Microbes Questions are directly based on NCERT, making it sufficient for preparation.
4. How can I revise this chapter quickly?
Focus on examples, practice PYQs, and revise key microbe-product pairs to master the Top 5 Microbes Questions.
