Explore topic-wise MCQs in Microbiology of Soils.

This section includes 37 Mcqs, each offering curated multiple-choice questions to sharpen your Microbiology of Soils knowledge and support exam preparation. Choose a topic below to get started.

1.

Which of the following is a symbiotic nitrogen fixing bacteria?

A. Rhizobium trifolii
B. Clostridium pasteurianum
C. Azotobacter sp.
D. Escherichia coli
Answer» B. Clostridium pasteurianum
2.

How much time does nitrifying bacteria requires to grow at an incubation of 250 to 300 C?

A. 1 day
B. 2-3 days
C. 15 days
D. 1 to 4 months
Answer» E.
3.

Ammonia oxidizers and nitrite oxidizers are ________________________

A. Gram-negative chemolithotrophs
B. Gram-positive chemolithotrophs
C. Gram-negative photolithotrophs
D. Gram-positive photolithotrophs
Answer» B. Gram-positive chemolithotrophs
4.

The reduction of sulphates and sulphites to hydrogen sulphide is done by which group of bacteria?

A. aerobic sulfate-reducing bacteria
B. photosynthetic sulphur bacteria
C. anaerobic sulphate-reducing bacteria
D. heterotrophic bacteria
Answer» D. heterotrophic bacteria
5.

The Winogradsky column experiment is done in the dark.

A. True
B. False
Answer» C.
6.

Sulphates are reduced to hydrogen sulphide by _____________________

A. Desulfotomaculum sp.
B. Thiobacillus thiooxidans
C. Photosynthetic sulfur bacteria
D. Rhodospirillum
Answer» B. Thiobacillus thiooxidans
7.

Cysteine breaks down in presence of cysteine desulfurase to give _________________

A. oxaloacetic acid
B. sulphuric acid
C. pyruvic acid
D. glyoxalate
Answer» D. glyoxalate
8.

Which of the following processes is performed by Thiobacillus thiooxidans?

A. converting sulphur to sulphates
B. converting sulphur to sulphides
C. converting sulphur to sulphites
D. converting organic sulphur to inorganic sulphur
Answer» B. converting sulphur to sulphides
9.

Cellobiose is metabolized directly by many microorganisms.

A. True
B. False
Answer» C.
10.

In carbon cycle flow of energy is _________________

A. bidirectional
B. linear
C. cyclic
D. irreversible
Answer» C. cyclic
11.

Denitrification is carried out

A. usually by facultative anaerobes
B. predominantly by Pseudomonas spp
C. predominantly by Bacillus spp
D. all of the above
Answer» E.
12.

The energy value of biogas is typically

A. 400-700 BTU/ft
B. 1,000 BTU/ft
C. 1500 BTU/ft
D. more than 5000 BTU/ft
Answer» B. 1,000 BTU/ft
13.

Ammonia oxidizers and nitrite oxidizers are ______________

A. Gram-negative chemolithotrophs
B. Gram-positive chemolithotrophs
C. Gram-negative photolithotrophs
D. Gram-positive photolithotrophs
Answer» B. Gram-positive chemolithotrophs
14.

Fresh air contains approximately ______ percent carbon dioxide by volume.

A. 0.01
B. 2
C. 5
D. 0.03
Answer» E.
15.

Which among the following are the most important agents for carbon dioxide fixation?

A. bacteria
B. fungi
C. algae
D. protozoa
Answer» D. protozoa
16.

Which of the following are not the features of component II of nitrogenase enzyme complex?

A. component II is nitrogenase reductase
B. component II is known as the MoFe protein
C. contains sulfur
D. not active without component I
Answer» C. contains sulfur
17.

Which of the following is symbiotic nitrogen fixing bacteria?

A. Rhizobium trifolii
B. Clostridium pasteurianum
C. Azotobacter sp.
D. Escherichia coli
Answer» B. Clostridium pasteurianum
18.

Which of the following conditions decreases the level of denitrification?

A. Abundance of organic matter
B. Acidic pH
C. Elevated temperatures
D. Availability of oxygen
Answer» C. Elevated temperatures
19.

How much time does nitrifying bacteria require to grow at an incubation of 250 to 300 C?

A. 1 day
B. 2-3 days
C. 15 days
D. 1 to 4 months
Answer» E.
20.

Agrobacterium is involved in which of the following processes?

A. Ammonification
B. Nitrification
C. Reduction of nitrate to ammonia
D. Denitrification
Answer» E.
21.

Nitrosococcus nitrosus is a nitrite-oxidizing bacteria.

A. True
B. False
Answer» C.
22.

Which among the following is not an ammonia-oxidizing bacteria?

A. Nitrosomonas europaea
B. Nitrosovibrio tenuis
C. Nitrospina gracilis
D. Nitrosococcus oceanus
Answer» D. Nitrosococcus oceanus
23.

Alanine gives pyruvic acid on deamination.

A. True
B. False
Answer» B. False
24.

The amount of organic material in the forest soil remains approximately the same from year to year.

A. True
B. False
Answer» B. False
25.

Cellulose is degraded to cellobiose by the enzyme __________________

A. cellulase
B. beta-glucosidase
C. hexokinase
D. cellulose dehydrogenase
Answer» B. beta-glucosidase
26.

The dominant mineral particles in most soils are compounds of _____________

A. sodium
B. potassium
C. magnesium
D. iron
Answer» E.
27.

Parasitism results from competition among organisms for essential nutrients.

A. True
B. False
C. May be
D. Can't say
Answer» C. May be
28.

Which of the following comes under the category of positive association?

A. neutralism
B. parasitism
C. commensalism
D. ammensalism
Answer» D. ammensalism
29.

Fungi produces which of the following inhibitory toxic product?

A. cyanide
B. fatty acids
C. methane
D. sulphides
Answer» B. fatty acids
30.

Lytic enzymes which destroy are secreted by which of the following microorganism?

A. fungi
B. algae
C. staphylococcus
D. myxobacteria
Answer» E.
31.

Which of the following types of association is present among Staphylococcus aureus and Aspergillus terreous?

A. antagonism
B. mutualism
C. parasitism
D. commensalism
Answer» B. mutualism
32.

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
Answer» D. Antagonism
33.

Which among the following is a non-sulfur purple bacteria?

A. Rhodomicrobium
B. Thiobacillus
C. Chromatium
D. Chlorobium
Answer» B. Thiobacillus
34.

The association which involves the exchange of nutrients between two species is referred to as ______________

A. mutualism
B. syntrophism
C. commensalism
D. antagonism
Answer» C. commensalism
35.

Bacteria are likely to be more prevalent in soils of vineyards, orchards and apiaries.

A. True
B. False
C. May be
D. Can't say
Answer» C. May be
36.

Which among the following develop in the upper portion of the Winogradsky column?

A. Sulfate-reducing bacteria
B. Green-sulfur bacteria
C. Purple-sulfur bacteria
D. Thiobacilli
Answer» E.
37.

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
Answer» D. yeast