Microbes in Human Welfare
Test 1

Correct answer Carries: 4.

Wrong Answer Carries: -1.

Which microorganism is responsible for the fermentation of milk into curd?

Saccharomyces cerevisiae
Lactobacillus
Penicillium
Clostridium
2

Lactobacillus bacteria convert lactose in milk to lactic acid, which helps in the formation of curd.

Which microorganism is used for the commercial production of ethanol?

Acetobacter aceti
Saccharomyces cerevisiae
Rhizobium
Bacillus subtilis
2

Saccharomyces cerevisiae, also known as brewer's yeast, is widely used in ethanol production.

Which of the following bacteria is used in the production of Swiss cheese?

Lactobacillus
Propionibacterium shermanii
Clostridium butylicum
Streptococcus
2

Propionibacterium shermanii produces CO₂ gas, creating holes in Swiss cheese.

Which of the following statements about biogas production is correct?

Methanogens are involved in biogas production.
Biogas mainly consists of oxygen and carbon dioxide.
Biogas is produced by aerobic bacteria.
Biogas plants work only at low temperatures.
1

Methanogens such as Methanobacterium are responsible for methane production in biogas plants.

Which of the following statements about microbes in sewage treatment is incorrect?

Primary treatment removes large and floating debris.
Aerobic bacteria are involved in secondary treatment.
Anaerobic digestion occurs in secondary treatment.
Activated sludge is used for further processing.
3

Anaerobic digestion occurs in the sludge treatment stage, not in secondary treatment.

Which of the following statements about antibiotics is correct?

Penicillin was discovered by Alexander Fleming.
Streptomycin is produced by Penicillium.
Antibiotics can kill viruses.
Erythromycin is produced by a bacterium.
1

Penicillin was discovered by Alexander Fleming in 1928, but the commercial production was later developed by Florey and Chain.

Which of the following statements regarding biofertilizers is incorrect?

Rhizobium fixes nitrogen in association with leguminous plants.
Azospirillum is a free-living nitrogen fixer.
Cyanobacteria like Nostoc are used as biofertilizers.
Biofertilizers cause pollution like chemical fertilizers.
4

Biofertilizers do not cause pollution; they naturally enrich the soil with essential nutrients.

Which microbe is used as a 'clot buster' in heart attack patients?

Trichoderma
Streptococcus
Aspergillus
Rhizobium
2

Streptococcus produces streptokinase, which helps dissolve blood clots.

Which gas is predominantly produced during biogas production?

Oxygen
Carbon dioxide
Methane
Nitrogen
3

Methane is the primary gas produced by methanogens in biogas plants.

Which antibiotic was discovered first?

Tetracycline
Streptomycin
Penicillin
Erythromycin
3

Penicillin was discovered by Alexander Fleming in 1928.

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