NEET 2025 MCQ with Answer Explanation : Microbes in Human Walefare.

Here below some basic MCQ’s of Microbes in human walefare with answer which is well explained. Let’s check one by one.

1. Which of the following microorganisms is used in the production of ethanol?
   A. Aspergillus niger
   B. Saccharomyces cerevisiae
   C. Penicillium chrysogenum
   D. Rhizopus stolonifer

Answer: B. Saccharomyces cerevisiae

Explanation:
Saccharomyces cerevisiae (commonly known as brewer’s yeast) is used in the fermentation of sugars to produce ethanol. This process is vital in brewing and baking industries.

2. Which of the following is not used as a biofertilizer?
   A. Rhizobium
   B. Azotobacter
   C. Mycorrhiza
   D. Lactobacillus

Answer: D. Lactobacillus

Explanation:
Lactobacillus is used in the production of dairy products like curd and is not involved in improving soil fertility. On the other hand, Rhizobium, Azotobacter, and Mycorrhiza are used to enhance plant growth by fixing nitrogen or increasing nutrient uptake.

3. Which microorganism is used for the production of the antibiotic penicillin?
   A. Streptomyces griseus
   B. Penicillium notatum
   C. Clostridium butylicum
   D. Lactobacillus bulgaricus

Answer: B. Penicillium notatum

Explanation:
Penicillium notatum was the original fungus from which penicillin was discovered by Alexander Fleming. It is widely used to produce this antibiotic, which is effective against a broad spectrum of bacteria.

4. What is the primary role of cyanobacteria in the environment?
   A. Methane production
   B. Photosynthesis and nitrogen fixation
   C. Lactic acid production
   D. Alcohol fermentation

Answer: B. Photosynthesis and nitrogen fixation

Explanation:
Cyanobacteria are important for their ability to perform oxygenic photosynthesis and fix atmospheric nitrogen, making them essential for both carbon and nitrogen cycles in the environment.

5. Which of the following microorganisms is used in the production of Swiss cheese?
   A. Penicillium roqueforti
   B. Streptococcus thermophilus
   C. Propionibacterium shermanii
   D. Saccharomyces cerevisiae

Answer: C. Propionibacterium shermanii

Explanation:
Propionibacterium shermanii is involved in the production of Swiss cheese and is responsible for the characteristic holes in the cheese, caused by the release of carbon dioxide during fermentation.

6. In the production of curd, which bacterium is commonly used?
   A. Lactobacillus acidophilus
   B. Escherichia coli
   C. Clostridium tetani
   D. Saccharomyces cerevisiae

Answer: A. Lactobacillus acidophilus

Explanation:
Lactobacillus acidophilus is commonly used in the fermentation process to convert lactose (milk sugar) into lactic acid, which results in the thickening of milk to form curd.

7. Which microorganism is used in the production of cyclosporin A, an immunosuppressive drug?
   A. Trichoderma polysporum
   B. Aspergillus niger
   C. Rhizobium
   D. Methanobacterium

Answer: A. Trichoderma polysporum

Explanation:
Trichoderma polysporum is a fungus used in the production of cyclosporin A, which is widely used as an immunosuppressive drug, especially during organ transplant procedures.

8. Which microorganism helps in the biogas production process?
   A. Rhizobium
   B. Methanobacterium
   C. Penicillium
   D. Azotobacter

Answer: B. Methanobacterium

Explanation:
Methanobacterium is a type of archaea involved in the production of methane (biogas) by breaking down organic matter anaerobically in biogas plants.

9. Which of the following microbes is involved in the production of citric acid?
   A. Penicillium chrysogenum
   B. Aspergillus niger
   C. Saccharomyces cerevisiae
   D. Rhizopus stolonifer

Answer: B. Aspergillus niger

Explanation:
Aspergillus niger is used industrially for the production of citric acid, which is used as a preservative and flavoring agent in the food and beverage industries.

10. The role of Rhizobium in agriculture is:
    A. Decomposition of organic matter
    B. Nitrogen fixation in leguminous plants
    C. Production of antibiotics
    D. Fermentation of sugars

Answer: B. Nitrogen fixation in leguminous plants

Explanation:
Rhizobium is a nitrogen-fixing bacterium that forms a symbiotic relationship with leguminous plants, converting atmospheric nitrogen into a form that the plants can utilize for growth.