This set of Microbiology Multiple Choice Questions & Answers (MCQs) focuses on “Interactions among Soil Microorganisms”.
1. The association which involves the exchange of nutrients between two species is referred to as ______________
a) mutualism
b) syntrophism
c) commensalism
d) antagonism
View Answer
Explanation: Syntrophism is a mutualistic association that involves the exchange of nutrients between two species.
2. The degradation of complex molecules in soil by fungi for utilization by bacteria is an example of which type of association?
a) Neutralism
b) Mutualism
c) Commensalism
d) Antagonism
View Answer
Explanation: Many bacteria are unable to utilize cellulose, but they can and do utilize the fungal breakdown products of cellulose e.g., glucose and organic acids. This phenomenon is referred to as commensalism.
3. Which of the following types of association is present among Staphylococcus aureus and Aspergillus terreous?
a) antagonism
b) mutualism
c) parasitism
d) commensalism
View Answer
Explanation: Staphylococcus aureus produces a diffusable antifungal material that causes distortions and hyphal swellings in Aspergillus terreous. This is an antagonistic relationship between these two organisms.
4. Lytic enzymes which destroy are secreted by which of the following microorganism?
a) fungi
b) algae
c) staphylococcus
d) myxobacteria
View Answer
Explanation: Myxobacteria (slime bacteria) and streptomycetes are antagonistic because they secrete potent lytic enzymes which destroy other cells by digesting their cell wall or other protective surface layers.
5. Fungi produces which of the following inhibitory toxic product?
a) cyanide
b) fatty acids
c) methane
d) sulphides
View Answer
Explanation: Cyanide is produced by certain fungi in concentrations toxic to other microorganisms.
6. Which of the following comes under the category of positive association?
a) neutralism
b) parasitism
c) commensalism
d) ammensalism
View Answer
Explanation: The phenomenon of commensalism is a positive type of association because it refers to a relationship between organisms in which one species of a pair benefits, the other is not affected.
7. Parasitism results from competition among organisms for essential nutrients.
a) True
b) False
View Answer
Explanation: Parasitism is defined as a relationship between organisms in which one organism lives in or on another organism referred to as a host.
8. The dominant mineral particles in most soils are compounds of _____________
a) sodium
b) potassium
c) magnesium
d) iron
View Answer
Explanation: The dominant mineral particles in most soils are compounds of silicon, aluminum, iron and lesser amounts of other minerals, including calcium, magnesium, potassium, sodium, nitrogen etc.
9. Bacteria are likely to be more prevalent in soils of vineyards, orchards and apiaries.
a) True
b) False
View Answer
Explanation: Yeasts are likely to be more prevalent in soils of vineyards, orchards, and apiaries, where special conditions, particularly the presence of sugars favor their growth.
10. Which of the following organisms are known to grow on the surfaces of freshly exposed rocks?
a) green algae
b) diatoms
c) cyanobacteria
d) yeast
View Answer
Explanation: Cyanobacteria, the oxygenic photosynthetic bacteria, are known to grow on the surfaces of freshly exposed rocks where the accumulation of their cells results in the simultaneous deposition of organic matter.
Sanfoundry Global Education & Learning Series – Microbiology.
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