The Redfield ratio is an index of concentration of

carbon, nitrogen and phosphorous

Nitrogen fixation by the microorganisms can be detected by adopting the approach of

demonstrating growth in a nitrogen free medium

cultivating the microorganisms in the presence of nitrogen labeled with isotropic nitrogen

measuring15N2 by mass spectrometer

Denitrification is carried out

usually by facultative anaerobes

predominantly by Pseudomonas spp

The red or pink color of the fish is generally caused from the growth of

Micrococcus or Bacillus species

The bacteria most often involved in the spoilage of fish are

part of the natural flora of the internal slime of fishes only

part of the natural flora of the external slime of fishes and their intestinal contents

part of the natural flora of the internal slime of fishes only

Agrobacterium is involved in which of the following processes?

Reduction of nitrate to ammonia

The groups of symbiotic bacteria, which have the ability to fix nitrogen

derive their food and minerals from the legume, and in turn they supply the legume with some or all of its nitrogen

grow together for a mutual benefit is called symbiosis and so these bacteria are called symbiotic nitrogen-fixing bacteria

these bacteria are from the genus, Rhizobium

In the process of nitrogen fixation, which of the following microorganism is involved?

Non symbiotic microorganisms only

Non symbiotic and symbiotic microorganisms only

The biological activity of an aquatic ecosystem is dependent upon which of the following factors?

amount of chemical energy produced

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

aerobic sulfate-reducing bacteria

photosynthetic sulphur bacteria

anaerobic sulphate-reducing bacteria

143 + Mcqs in Soil and Aquatic Microbiology in Microbiology Page 2 McqOptions

51.	The Redfield ratio is an index of concentration of
A.	carbon, hydrogen and oxygen
B.	nitrogen, potassium and iron
C.	carbon, nitrogen and phosphorous
D.	carbon, phosphorous and sulfur
Answer» D. carbon, phosphorous and sulfur

Discussion

52.	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

Discussion

53.	Which of the following compounds are required for growth of saprophytic bacteria and fungi?
A.	organic compounds
B.	nitrates
C.	phosphates
D.	mercury
Answer» B. nitrates

Discussion

54.	Which among the following are the most important agents for carbon dioxide fixation?
A.	bacteria
B.	fungi
C.	algae
D.	protozoa
Answer» D. protozoa

Discussion

55.	Which of the following layer is composed of soft mud or ooze?
A.	Photic zone
B.	Limnetic zone
C.	Benthic zone
D.	Profundal zone
Answer» D. Profundal zone

Discussion

56.	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

Discussion

57.	The crops which are involved in nitrogen fixation are
A.	alfalfa and clover
B.	soybean
C.	bean and lupine
D.	all of these
Answer» E.

Discussion

58.	Nitrogen fixation by the microorganisms can be detected by adopting the approach of
A.	demonstrating growth in a nitrogen free medium
B.	cultivating the microorganisms in the presence of nitrogen labeled with isotropic nitrogen
C.	measuring15N2 by mass spectrometer
D.	all of the above
Answer» E.

Discussion

59.	The amount of organic material in the forest soil remains approximately the same from year to year.
A.	True
B.	False
C.	May be
D.	Can't say
Answer» B. False

Discussion

60.	Cellulose is degraded to cellobiose by the enzyme __________________
A.	cellulase
B.	beta-glucosidase
C.	hexokinase
D.	cellulose dehydrogenase
Answer» B. beta-glucosidase

Discussion

61.	Fresh air contains approximately ______ percent carbon dioxide by volume.
A.	0.01
B.	2
C.	5
D.	0.03
Answer» E.

Discussion

62.	In carbon cycle flow of energy is _________________
A.	bidirectional
B.	linear
C.	cyclic
D.	irreversible
Answer» C. cyclic

Discussion

63.	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

Discussion

64.	Parasitism results from competition among organisms for essential nutrients.
A.	True
B.	False
C.	May be
D.	Can't say
Answer» C. May be

Discussion

65.	Hydrostatic pressure increases the boiling point of water but does not change the solubility of nutrients.
A.	True
B.	False
C.	May be
D.	Can't say
Answer» C. May be

Discussion

66.	Alanine gives pyruvic acid on deamination.
A.	True
B.	False
C.	May be
D.	Can't say
Answer» B. False

Discussion

67.	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.

Discussion

68.	Nitrosococcus nitrosus is a nitrite-oxidizing bacteria.
A.	True
B.	False
C.	May be
D.	Can't say
Answer» C. May be

Discussion

69.	Thermus aquaticus, a common bacterial inhabitant generally prevails in temperatures of ____________
A.	0° C
B.	30-40°C
C.	70-72°C
D.	80-85°C
Answer» D. 80-85°C

Discussion

70.	Primary producers are found growing in which of the following layers of water?
A.	upper layer
B.	middle layer
C.	intermediate layer
D.	bottom layer
Answer» B. middle layer

Discussion

71.	Which of the following is subterranean water?
A.	Atmospheric water
B.	Surface water
C.	Groundwater
D.	Rainwater
Answer» D. Rainwater

Discussion

72.	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.

Discussion

73.	An example of a symbiotic nitrogen fixer is
A.	Azotobacter
B.	Beijerinckia
C.	Clostridium
D.	Rhizobium
Answer» E.

Discussion

74.	The dominant mineral particles in most soils are compounds of _____________
A.	sodium
B.	potassium
C.	magnesium
D.	iron
Answer» E.

Discussion

75.	Denitrification may be distinguished as
A.	dissimilative
B.	assimilative
C.	both (a) and (b)
D.	blue baby syndrome
Answer» D. blue baby syndrome

Discussion

76.	Which of the following comes under the category of positive association?
A.	neutralism
B.	parasitism
C.	commensalism
D.	ammensalism
Answer» D. ammensalism

Discussion

77.	The red or pink color of the fish is generally caused from the growth of
A.	Sarcina
B.	Micrococcus or Bacillus species
C.	Molds or yeasts
D.	all of these
Answer» E.

Discussion

78.	The bacteria most often involved in the spoilage of fish are
A.	part of the natural flora of the external slime of fishes and their intestinal contents
B.	part of the natural flora of the internal slime of fishes only
C.	both (a) and (b)
D.	none of the above
Answer» B. part of the natural flora of the internal slime of fishes only

Discussion

79.	The amount of oxygen dissolved in hypolimnion water in the winter is __________ to/than the amount of oxygen dissolved in hypolimnion water in the summer
A.	greater
B.	lesser
C.	approximately equal to
D.	half
Answer» B. lesser

Discussion

80.	Agrobacterium is involved in which of the following processes?
A.	Ammonification
B.	Nitrification
C.	Reduction of nitrate to ammonia
D.	Denitrification
Answer» E.

Discussion

81.	The population of algae in soil is __________ that of either bacteria or fungi.
A.	generally smaller than
B.	generally greater than
C.	equal to
D.	none of these
Answer» B. generally greater than

Discussion

82.	The groups of bacteria which have the ability to fix nitrogen from air to soil are
A.	symbiotic
B.	nonsymbiotic
C.	both (a) and (b)
D.	none of these
Answer» D. none of these

Discussion

83.	Which among the following factors are limiting growth of phytoplankton organisms?
A.	carbon dioxide
B.	radiant energy
C.	water
D.	radiant energy,nitrogen
Answer» E.

Discussion

84.	Which of the following zones have considerable rooted vegetation?
A.	littoral zone
B.	limnetic zone
C.	profundal zone
D.	benthic zone
Answer» B. limnetic zone

Discussion

85.	Which of the following species of different genera of bacteria are not capable of transforming nitrate to nitrogen?
A.	Achromobacter
B.	Agrobacterium
C.	Alcaligenes
D.	None of these
Answer» E.

Discussion

86.	Which of the following is capable of oxidizing sulfur to sulfates?
A.	Thiobacillus thiooxidans
B.	Desulfotomaculum
C.	Rhodospirillum
D.	Rhodomicrobium
Answer» B. Desulfotomaculum

Discussion

87.	The groups of symbiotic bacteria, which have the ability to fix nitrogen
A.	derive their food and minerals from the legume, and in turn they supply the legume with some or all of its nitrogen
B.	grow together for a mutual benefit is called symbiosis and so these bacteria are called symbiotic nitrogen-fixing bacteria
C.	these bacteria are from the genus, Rhizobium
D.	all of the above
Answer» E.

Discussion

88.	In the process of nitrogen fixation, which of the following microorganism is involved?
A.	Non symbiotic microorganisms only
B.	Symbiotic microorganisms only
C.	Non symbiotic and symbiotic microorganisms only
D.	None of the above
Answer» D. None of the above

Discussion

89.	Protozoa and other minute animal life are known as ____________________
A.	plankton
B.	phytoplankton
C.	zooplankton
D.	mycoplankton
Answer» D. mycoplankton

Discussion

90.	The diagnostic enzyme for nitrogen-fixing organisms is
A.	nitrogenase
B.	nitrate reductase
C.	nitrate oxidase
D.	none of these
Answer» B. nitrate reductase

Discussion

91.	The biological activity of an aquatic ecosystem is dependent upon which of the following factors?
A.	number of primary producers
B.	amount of chemical energy produced
C.	rate of primary production
D.	number of deaths of organisms
Answer» D. number of deaths of organisms

Discussion

92.	Which are the main source of biofertilisers?
A.	Cyanobacteria
B.	Bacillus
C.	Streptococcus
D.	None of these
Answer» B. Bacillus

Discussion

93.	Degree of compost maturity can be assesed by
A.	infrared technique
B.	germination test
C.	both (a) and (b)
D.	none of the above
Answer» D. none of the above

Discussion

94.	The transformation of nitrates to gaseous nitrogen is accomplished by microorganisms in a series of biochemical reactions. The process is known as
A.	nitrification
B.	denitrification
C.	nitrogen fixation
D.	ammonification
Answer» C. nitrogen fixation

Discussion

95.	The term fertility of oceans is used to express the capacity for production of inorganic matter.
A.	True
B.	False
C.	May be
D.	Can't say
Answer» C. May be

Discussion

96.	The Winogradsky column experiment is done in the dark.
A.	True
B.	False
C.	May be
D.	Can't say
Answer» C. May be

Discussion

97.	Sulphates are reduced to hydrogen sulphide by _____________________
A.	Desulfotomaculum sp.
B.	Thiobacillus thiooxidans
C.	Photosynthetic sulfur bacteria
D.	Rhodospirillum
Answer» B. Thiobacillus thiooxidans

Discussion

98.	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

Discussion

99.	The moisture contained in clouds and precipitated as snow,hail,rain etc constitutes _________________
A.	Atmospheric water
B.	Surface water
C.	Groundwater
D.	Subterranean water
Answer» B. Surface water

Discussion

100.	Which among the following is a non-sulfur purple bacteria?
A.	Rhodomicrobium
B.	Thiobacillus
C.	Chromatium
D.	Chlorobium
Answer» B. Thiobacillus

Discussion

Explore topic-wise MCQs in Microbiology.

The Redfield ratio is an index of concentration of

Which of the following conditions decreases the level of denitrification?

Which of the following compounds are required for growth of saprophytic bacteria and fungi?

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

Which of the following layer is composed of soft mud or ooze?

Which of the following organisms are known to grow on the surfaces of freshly exposed rocks?

The crops which are involved in nitrogen fixation are

Nitrogen fixation by the microorganisms can be detected by adopting the approach of

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

Cellulose is degraded to cellobiose by the enzyme __________________

Fresh air contains approximately ______ percent carbon dioxide by volume.

In carbon cycle flow of energy is _________________

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

Parasitism results from competition among organisms for essential nutrients.

Hydrostatic pressure increases the boiling point of water but does not change the solubility of nutrients.

Alanine gives pyruvic acid on deamination.

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

Nitrosococcus nitrosus is a nitrite-oxidizing bacteria.

Thermus aquaticus, a common bacterial inhabitant generally prevails in temperatures of ____________

Primary producers are found growing in which of the following layers of water?

Which of the following is subterranean water?

Denitrification is carried out

An example of a symbiotic nitrogen fixer is

The dominant mineral particles in most soils are compounds of _____________

Denitrification may be distinguished as

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

The red or pink color of the fish is generally caused from the growth of

The bacteria most often involved in the spoilage of fish are

The amount of oxygen dissolved in hypolimnion water in the winter is __________ to/than the amount of oxygen dissolved in hypolimnion water in the summer

Agrobacterium is involved in which of the following processes?

The population of algae in soil is __________ that of either bacteria or fungi.

The groups of bacteria which have the ability to fix nitrogen from air to soil are

Which among the following factors are limiting growth of phytoplankton organisms?

Which of the following zones have considerable rooted vegetation?

Which of the following species of different genera of bacteria are not capable of transforming nitrate to nitrogen?

Which of the following is capable of oxidizing sulfur to sulfates?

The groups of symbiotic bacteria, which have the ability to fix nitrogen

In the process of nitrogen fixation, which of the following microorganism is involved?

Protozoa and other minute animal life are known as ____________________

The diagnostic enzyme for nitrogen-fixing organisms is

The biological activity of an aquatic ecosystem is dependent upon which of the following factors?

Which are the main source of biofertilisers?

Degree of compost maturity can be assesed by

The transformation of nitrates to gaseous nitrogen is accomplished by microorganisms in a series of biochemical reactions. The process is known as

The term fertility of oceans is used to express the capacity for production of inorganic matter.

The Winogradsky column experiment is done in the dark.

Sulphates are reduced to hydrogen sulphide by _____________________

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

The moisture contained in clouds and precipitated as snow,hail,rain etc constitutes _________________

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