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Microorganisms: Friend and Foe Practice Questions

Class 8 · Science · 1218 free MCQs with instant results and detailed explanations.

1218
Total
367
Easy
609
Medium
242
Hard

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Topics in Microorganisms: Friend and Foe

Types of Microorganisms 305
Harmful Microorganisms 307
Useful Microorganisms 307
Food Preservation 299

Sample Questions from Microorganisms: Friend and Foe

Here are 10 sample questions. Start a quiz to get randomized questions with scoring.

Q1
Easy
Which of the following microorganisms is primarily used in the production of yogurt?
A. Bacteria
B. Virus
C. Protozoa
D. Fungi
Show Answer & Explanation
Correct Answer: A
Bacteria, especially Lactobacillus, are used to ferment milk into yogurt.
Q2
Easy
Which type of microorganism is known for being a single-celled organism that can perform photosynthesis?
A. Bacteria
B. Algae
C. Fungi
D. Viruses
Show Answer & Explanation
Correct Answer: B
Algae are simple, photosynthetic organisms that can be unicellular or multicellular.
Q3
Easy
Which microorganism is responsible for the fermentation of bread dough?
A. Protozoa
B. Yeast
C. Bacteria
D. Virus
Show Answer & Explanation
Correct Answer: B
Yeast, a type of fungus, ferments sugars in bread dough, producing carbon dioxide that makes the bread rise.
Q4
Medium
Which of the following microorganisms is known for nitrogen fixation in soil?
A. Rhizobium
B. Streptococcus
C. E. coli
D. Yeast
Show Answer & Explanation
Correct Answer: A
Rhizobium is a bacterium that forms symbiotic relationships with legumes to fix atmospheric nitrogen, enriching soil fertility.
Q5
Medium
Which of the following diseases is NOT caused by a virus?
A. Influenza
B. Chickenpox
C. Malaria
D. Hepatitis
Show Answer & Explanation
Correct Answer: C
Malaria is caused by the Plasmodium parasite, while the other diseases listed are viral infections.
Q6
Medium
Which microorganism is primarily used in the fermentation process of bread?
A. Lactobacillus
B. Saccharomyces cerevisiae
C. Escherichia coli
D. Penicillium
Show Answer & Explanation
Correct Answer: B
Saccharomyces cerevisiae, commonly known as yeast, ferments sugars in dough, producing carbon dioxide that causes bread to rise.
Q7
Medium
Which of the following microorganisms can be used in bioremediation to clean up environmental pollutants?
A. Bacillus thuringiensis
B. Pseudomonas aeruginosa
C. Saccharomyces cerevisiae
D. Clostridium difficile
Show Answer & Explanation
Correct Answer: B
Pseudomonas aeruginosa is known for its ability to degrade various environmental pollutants, making it useful in bioremediation efforts.
Q8
Hard
Which of the following microorganisms can be used in the production of antibiotics?
A. Bacteria
B. Viruses
C. Fungi
D. Algae
Show Answer & Explanation
Correct Answer: C
Fungi, particularly Penicillium species, are known to produce antibiotics like penicillin.
Q9
Hard
Which of the following diseases is NOT caused by a virus?
A. Influenza
B. Tuberculosis
C. Chickenpox
D. HIV/AIDS
Show Answer & Explanation
Correct Answer: B
Tuberculosis is caused by the bacterium Mycobacterium tuberculosis, not a virus.
Q10
Hard
What type of microorganism is commonly used in the fermentation of yogurt?
A. Protozoa
B. Bacteria
C. Fungi
D. Algae
Show Answer & Explanation
Correct Answer: B
Bacteria such as Lactobacillus are used to ferment milk into yogurt.

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Microorganisms: Friend and Foe — Class 8 Science Practice Questions Online

This page contains 1218 practice MCQs for the chapter Microorganisms: Friend and Foe in Class 8 Science. The questions are organized by difficulty — 367 easy, 609 medium, 242 hard — so you can choose the right level for your preparation.

Every question includes a detailed explanation to help you understand the concept, not just memorize answers. Take a timed quiz to simulate exam conditions, or practice at your own pace with no time limit. This chapter covers 4 topics, giving you comprehensive coverage of the entire chapter.