Useful & Harmful Micro-organisms — Homi Bhabha Exam Biology MCQs with Solutions
Free Homi Bhabha Exam Biology Useful & Harmful Micro-organisms MCQs with step-by-step solutions (7 questions). Part of Biotechnology & Applied Biology. Practise online on Prepizo — no login needed.
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Questions with solutions
Q1 — Useful & Harmful Micro-organisms · medium · theory
The microorganism used to convert milk into curd is:
A. Plasmodium
B. a fern
C. a virus
D. Lactobacillus (bacteria) ✓ Correct
Solution: Lactobacillus bacteria ferment milk into curd.
Q2 — Useful & Harmful Micro-organisms · medium · theory
Yeast is useful in bakeries and breweries because it carries out:
A. photosynthesis
B. digestion
C. fermentation ✓ Correct
D. nitrogen fixation
Solution: Yeast ferments sugars to produce carbon dioxide and alcohol.
Q3 — Useful & Harmful Micro-organisms · hard · theory
Medicines that are produced from microorganisms and used to treat bacterial diseases are called:
A. vaccines
B. antibiotics ✓ Correct
C. hormones
D. vitamins
Solution: Antibiotics (e.g. penicillin) are made from microbes and kill or stop bacteria.
Q4 — Useful & Harmful Micro-organisms · medium · theory
Which of the following is a HARMFUL effect of microorganisms?
A. Spoiling food and causing diseases ✓ Correct
B. Fixing nitrogen in soil
C. Making curd
D. Producing antibiotics
Solution: Some microbes spoil food and cause diseases, which are harmful effects.
Q5 — Useful & Harmful Micro-organisms · hard · theory
Food is preserved by methods like refrigeration and salting mainly to:
A. slow down or stop the growth of microorganisms ✓ Correct
B. increase spoilage
C. add colour
D. add more microbes
Solution: Preservation prevents microbial growth that would otherwise spoil the food.
Q6 — Useful & Harmful Micro-organisms · medium · theory
Disease-causing microorganisms are known as:
A. decomposers
B. saprophytes
C. pathogens ✓ Correct
D. producers
Solution: Pathogens are microbes that cause disease in their host.
Q7 — Useful & Harmful Micro-organisms · hard · theory
The mould Penicillium is important because it produces the antibiotic:
A. vinegar
B. insulin
C. penicillin ✓ Correct
D. ethanol
Solution: Penicillium yields penicillin, the first widely used antibiotic.