Microbes in Human Welfare is a Class 12 Biology chapter that carries about 1.9% of the Biology questions in NEET. Practise it with 43 questions covering 4 topics, each with an explanation.
Sample questions on Microbes in Human Welfare with answers
8 questions from the practice bank, spread across the chapter's topics. The full set is in the app.
Question 1: Microbes as Biocontrol Agents and Biofertilizers
Biocontrol agents, such as certain fungi and bacteria, are used in agriculture as an eco-friendly alternative to:
- A irrigation systems
- B chemical pesticides and fertilizers
- C crop rotation
- D greenhouse farming
Answer: B. chemical pesticides and fertilizers
Why: Biocontrol agents (like Trichoderma or Bacillus thuringiensis) control pests and pathogens naturally, offering an environmentally friendly alternative to synthetic chemical pesticides.
Question 2: Microbes as Biocontrol and Biofertilizers
Rhizobium bacteria act as a biofertilizer chiefly because they:
- A produce antibiotics against pathogens
- B fix atmospheric nitrogen in root nodules of leguminous plants
- C decompose dead organic matter
- D produce plant growth hormones only
Answer: B. fix atmospheric nitrogen in root nodules of leguminous plants
Why: Living symbiotically in root nodules of legumes, Rhizobium converts atmospheric nitrogen into a form plants can use, enriching soil fertility without chemical fertilizer.
Question 3: Microbes in Food and Industrial Products
Lipases, used in the detergent formulations, help to:
- A remove oily stains from the laundry
- B clean the metals
- C reduce foam
- D whiten the clothes
Answer: A. remove oily stains from the laundry
Why: The enzymes are produced by microbes.
Question 4: Microbes in Food and Industry
Biogas (gobar gas) is produced from cattle dung by:
- A methanogenic bacteria such as Methanobacterium
- B Aspergillus
- C Lactobacillus
- D Rhizobium
Answer: A. methanogenic bacteria such as Methanobacterium
Why: Anaerobic digestion by these archaebacteria yields mainly methane, with CO₂ and H₂.
Question 5: Microbes as Biocontrol Agents and Biofertilizers
Which of the following is used as a biofertilizer that fixes atmospheric nitrogen in leguminous plants?
- A Rhizobium
- B Trichoderma
- C Bacillus thuringiensis
- D Baculovirus
Answer: A. Rhizobium
Why: Rhizobium bacteria form a symbiotic relationship with the roots of leguminous plants, fixing atmospheric nitrogen into a usable form.
Question 6: Microbes in Food and Industrial Products
Antibiotics, such as penicillin, are commercially produced using:
- A genetically modified plants
- B microorganisms like fungi and bacteria
- C synthetic chemicals only
- D animal cell cultures exclusively
Answer: B. microorganisms like fungi and bacteria
Why: Antibiotics like penicillin are produced through the large-scale culturing of microorganisms — penicillin itself is derived from the fungus Penicillium.
Question 7: Microbes in Food and Industry
The fermentation of milk into curd is carried out by:
- A Saccharomyces cerevisiae
- B Lactobacillus and related bacteria
- C Aspergillus niger
- D Penicillium notatum
Answer: B. Lactobacillus and related bacteria
Why: Lactobacillus and other lactic acid bacteria ferment lactose in milk to lactic acid, curdling and preserving it as curd/yoghurt.
Question 8: Microbes as Biocontrol Agents and Biofertilizers
Baculoviruses are mostly used as biological control agents against:
- A insects and other arthropods, being species-specific and narrow spectrum
- B bacteria
- C fungi
- D plants
Answer: A. insects and other arthropods, being species-specific and narrow spectrum
Why: The genus Nucleopolyhedrovirus is an example.
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