Nitrogen oxidation (nitrification)refers to the

changing of atmospheric nitrogen (N2) to nitrogen compounds

conversion of ammonium ions into nitrates through the activities of certain bacteria.

changing of atmospheric nitrogen (N2) to nitrogen compounds

sulfur is oxidized to the sulfate form through Thiobacillus bacteria

exchange of nutrients among species

exchange of nutrients between two species

exchange of nutrients among species

no exchange of nutrients between two species

no exchange of nutrients among species

The phenomenon of commensalism refers to a relationship between organisms in which

both the species of a pair benefit

one species of a pair is more benefited

produce nonmotile tetaradiate conidia

grow in leaves and the infected leaves are the preferred food source for some aquatic insects

The nonsymbiotic bacteria which fix nitrogen live in the soil independently are

considerably less important in comparison to the symbiotic bacteria

Coliforms are used as indicator organisms because

they are present wherever enteric pathogens are present

a testing procedure with great specificity is easy to perform

the progenitor of cyanobacterial vegetative cells

a terminally differentiated cell that fixes nitrogen

the progenitor of cyanobacterial vegetative cells

a cell that carries out oxygenic photosynthesis

The primary producers in the marine system are ________________

cyanobacteria and eukaryotic algae

In chilled shrimp __________ is chiefly responsible for spoilage.

Micrococcus or Bacillus species

The sulfur pearl of Namibia, Thiomargarita namibiensis

is the worlds smallest bacterium

is the worlds largest bacterium

stores high concentrations of nitrate in a huge internal vacuole which takes up 98% of the organisms volume

is the worlds smallest bacterium

Which of the following techniques can be used to separate different-size fractions of the aquatic microbial community?

by measuring biochemical activity

__________ is an environment like __________ where microorganisms are functioning in an extremely thin film of water and where oxygen-containing air is close to them.

low oxygen diffusion environment; lakes

low oxygen diffusion environment; soils

high oxygen diffusion environment; soils

low oxygen diffusion environment; lakes

high oxygen diffusion environment; lakes

143 + Mcqs in Soil and Aquatic Microbiology in Microbiology Page 1 McqOptions

1.	Nitrogen oxidation (nitrification)refers to the
A.	conversion of ammonium ions into nitrates through the activities of certain bacteria.
B.	changing of atmospheric nitrogen (N2) to nitrogen compounds
C.	sulfur is oxidized to the sulfate form through Thiobacillus bacteria
D.	none of the above
Answer» B. changing of atmospheric nitrogen (N2) to nitrogen compounds

Discussion

2.	In which of the following water bodies, fertility is high?
A.	open sea
B.	coastal regions
C.	lakes
D.	rivers
Answer» C. lakes

Discussion

3.	Aquatic bacteria tend to be Gram-negative.
A.	True
B.	False
C.	May be
D.	Can't say
Answer» B. False

Discussion

4.	Which of the following water bodies, the role of photosynthetic organisms is considerably reduced?
A.	Lakes
B.	Ponds
C.	Estuaries
D.	Streams
Answer» D. Streams

Discussion

5.	The Chesapeake Bay, one of the world’s major estuarine system serves as the receiving basin for how many rivers?
A.	4
B.	6
C.	3
D.	9
Answer» E.

Discussion

6.	Some microorganisms have the ability to increase the nitrogen content of soils, are called as
A.	nitrogen fixation
B.	denitrification
C.	nitrification
D.	all of these
Answer» B. denitrification

Discussion

7.	The energy value of biogas is typically
A.	400-700 BTU/ft3
B.	1,000 BTU/ft3
C.	1500 BTU/ft3
D.	more than 5000 BTU/ft3
Answer» B. 1,000 BTU/ft3

Discussion

8.	Nitrifying bacteria can not be isolated directly by the usual techniques employed to isolate hetrotrophic bacteria. The reasons may be due to
A.	slow growth
B.	medium growth
C.	fast growth
D.	none of these
Answer» B. medium growth

Discussion

9.	What amount of dry organic matter is produced by the deep ocean areas?
A.	1g
B.	10g
C.	0.5g
D.	100g
Answer» D. 100g

Discussion

10.	The diagnostic enzyme for denitrification is
A.	nitrate reductase
B.	nitrate oxidase
C.	nitro oxidoreductase
D.	none of these
Answer» B. nitrate oxidase

Discussion

11.	Which of the following organism have siliceous skeletons?
A.	Foraminifera
B.	Coccolithophores
C.	Radiolaria
D.	Cyanobacteria
Answer» D. Cyanobacteria

Discussion

12.	Which of the following product is not obtained from dissimilation of organic matter under aerobic conditions?
A.	ammonium
B.	sulphate
C.	methane
D.	phosphate
Answer» D. phosphate

Discussion

13.	Syntrophism involves
A.	exchange of nutrients between two species
B.	exchange of nutrients among species
C.	no exchange of nutrients between two species
D.	no exchange of nutrients among species
Answer» B. exchange of nutrients among species

Discussion

14.	Which of the following soil microorganism is involved in the reduction of sulfates to H2S?
A.	Thiobacillus thiooxidans
B.	Desulfotomaculum
C.	Rhodospirillum
D.	Rhodomicrobium
Answer» C. Rhodospirillum

Discussion

15.	Which of the following fungi on infecting crop roots can improve their uptake of phosphorus and other nutrients?
A.	Saccharomyces cerevisiae
B.	VA Mycorrhiza
C.	Candida torulopsis
D.	Aspergillus niger
Answer» C. Candida torulopsis

Discussion

16.	The phenomenon of commensalism refers to a relationship between organisms in which
A.	one species of a pair benefits
B.	both the species of a pair benefit
C.	one species of a pair is more benefited
D.	none of the above
Answer» B. both the species of a pair benefit

Discussion

17.	Hyphomycete fungi
A.	produce nonmotile tetaradiate conidia
B.	grow in leaves and the infected leaves are the preferred food source for some aquatic insects
C.	both (a) and (b)
D.	none of the above
Answer» D. none of the above

Discussion

18.	The chief spoilage organisms on smoked fish are
A.	molds
B.	bacteria
C.	both (a) and (b)
D.	fungi
Answer» B. bacteria

Discussion

19.	Bacteria, as a group, are responsible for
A.	nitrogen oxidation
B.	sulfur oxidation
C.	nitrogen fixation
D.	all of these
Answer» E.

Discussion

20.	Which among the following oceans is the most richest in life?
A.	Antarctic Ocean
B.	Atlantic Ocean
C.	Pacific Ocean
D.	Indian Ocean
Answer» B. Atlantic Ocean

Discussion

21.	The physical structure of soil is improved by the accumulation of
A.	mold mycelium
B.	minerals
C.	water
D.	all of these
Answer» B. minerals

Discussion

22.	Marinated (sour pickled) fish should not have spoilage problems unless
A.	the acid content is very high
B.	the acid content is low enough
C.	the acid content is moderate
D.	none of the above
Answer» C. the acid content is moderate

Discussion

23.	The organisms responsible for the characteristic musty or earth odor of a freshly plowed field is/are
A.	Nocardia
B.	Streptomyces
C.	Micromonospora
D.	all of these
Answer» E.

Discussion

24.	Loss of carbon through the microbial loop in oligotrophic environments is __________ to/than the loss of carbon through the microbial loop in copiotrophic environments.
A.	greater
B.	lesser
C.	approximately equal
D.	half
Answer» B. lesser

Discussion

25.	Chemical precipitation of phosphorus is
A.	primary treatment
B.	secondary treatment
C.	tertiary treatment
D.	both (a) and (b)
Answer» D. both (a) and (b)

Discussion

26.	Which of the following aquatic organisms contribute in a small amount to the shallow estuary food web?
A.	benthic algae
B.	bacteria
C.	protozoa
D.	nematodes
Answer» B. bacteria

Discussion

27.	The nonsymbiotic bacteria which fix nitrogen live in the soil independently are
A.	Azotobacter
B.	Clostridium
C.	considerably less important in comparison to the symbiotic bacteria
D.	all of the above
Answer» E.

Discussion

28.	Coliforms are used as indicator organisms because
A.	they are present wherever enteric pathogens are present
B.	a testing procedure with great specificity is easy to perform
C.	both (a) and (b)
D.	none of the above
Answer» D. none of the above

Discussion

29.	A heterocyst is
A.	a type of spore
B.	a terminally differentiated cell that fixes nitrogen
C.	the progenitor of cyanobacterial vegetative cells
D.	a cell that carries out oxygenic photosynthesis
Answer» C. the progenitor of cyanobacterial vegetative cells

Discussion

30.	The primary producers in the marine system are ________________
A.	protozoa
B.	cyanobacteria
C.	fungi
D.	cyanobacteria and eukaryotic algae
Answer» E.

Discussion

31.	In chilled shrimp __________ is chiefly responsible for spoilage.
A.	Achromobacter
B.	Pseudomonas
C.	Micrococcus or Bacillus species
D.	Molds or yeasts
Answer» B. Pseudomonas

Discussion

32.	The sulfur pearl of Namibia, Thiomargarita namibiensis
A.	is the worlds largest bacterium
B.	stores high concentrations of nitrate in a huge internal vacuole which takes up 98% of the organisms volume
C.	Both (a) and (b)
D.	is the worlds smallest bacterium
Answer» D. is the worlds smallest bacterium

Discussion

33.	The coastal adjunct of the marine ecosystem is __________________
A.	stream
B.	estuary
C.	river
D.	lake
Answer» C. river

Discussion

34.	Which of the following techniques can be used to separate different-size fractions of the aquatic microbial community?
A.	submerged-slide technique
B.	fluorescent antibody technique
C.	membrane-filter technique
D.	by measuring biochemical activity
Answer» D. by measuring biochemical activity

Discussion

35.	Because it can be used with a variety of media and allow a resuscitation step the __________ technique has become the common and often preferred method of evaluating the microbiological characteristics of water.
A.	most probable number
B.	Winogradsky
C.	MUG
D.	membrane filtration
Answer» E.

Discussion

36.	All of the following species are considered coliforms except
A.	Enterobacter aerogenes
B.	Klebsiella pneumoniae
C.	Salmonella typhi
D.	Escherichia coli
Answer» D. Escherichia coli

Discussion

37.	At higher temperatures, the souring of Oysters may be the result of the fermentation of sugars by
A.	Coliform bacteria
B.	Streptococci
C.	Lactobacilli and yeast
D.	all of these
Answer» E.

Discussion

38.	Removal of solids is generally considered as a
A.	Primary treatment
B.	Secondary treatment
C.	Tertiary treatment
D.	None of these
Answer» B. Secondary treatment

Discussion

39.	In which of the following seasons does the nutrient concentration falls at a drastically lower level?
A.	Winter
B.	Spring
C.	Summer
D.	Autumn
Answer» D. Autumn

Discussion

40.	The nitrogenase consists of
A.	dinitrogenase
B.	dinitrogenase reductase
C.	both (a) and (b)
D.	none of these
Answer» D. none of these

Discussion

41.	Which of the following techniques is used for identification and enumeration of algae, bacteria, protozoa?
A.	Microscopic examination
B.	Submerged-slide technique
C.	Membrane-filter technique
D.	Enrichment-culture technique
Answer» B. Submerged-slide technique

Discussion

42.	Most aquatic microorganisms can grow on the usual laboratory media.
A.	True
B.	False
C.	May be
D.	Can't say
Answer» C. May be

Discussion

43.	Large spiraling surface currents in the ocean that tend to aggregate and retain nutrients are known as _______________
A.	benthic region
B.	upwelling
C.	geothermal vents
D.	gyres
Answer» E.

Discussion

44.	Phytoplanktonic organisms are non-motile.
A.	True
B.	False
C.	May be
D.	Can't say
Answer» C. May be

Discussion

45.	The degree of salinity in freshwater is nearly zero.
A.	True
B.	False
C.	May be
D.	Can't say
Answer» B. False

Discussion

46.	The microorganisms from lakes and rivers can grow at a salt concentration of _________
A.	2.5 to 4 percent
B.	5 percent
C.	below 1 percent
D.	above 1 percent
Answer» D. above 1 percent

Discussion

47.	The rate of flux of oxygen in air is __________ to/than the rate of flux of oxygen in water.
A.	greater
B.	lesser
C.	approximately equal
D.	half
Answer» B. lesser

Discussion

48.	__________ is an environment like __________ where microorganisms are functioning in an extremely thin film of water and where oxygen-containing air is close to them.
A.	low oxygen diffusion environment; soils
B.	high oxygen diffusion environment; soils
C.	low oxygen diffusion environment; lakes
D.	high oxygen diffusion environment; lakes
Answer» C. low oxygen diffusion environment; lakes

Discussion

49.	Activated sludge undergoes
A.	Primary treatment
B.	Secondary treatment
C.	Tertiary treatment
D.	any of these
Answer» C. Tertiary treatment

Discussion

50.	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

Discussion

Explore topic-wise MCQs in Microbiology.

Nitrogen oxidation (nitrification)refers to the

In which of the following water bodies, fertility is high?

Aquatic bacteria tend to be Gram-negative.

Which of the following water bodies, the role of photosynthetic organisms is considerably reduced?

The Chesapeake Bay, one of the world’s major estuarine system serves as the receiving basin for how many rivers?

Some microorganisms have the ability to increase the nitrogen content of soils, are called as

The energy value of biogas is typically

Nitrifying bacteria can not be isolated directly by the usual techniques employed to isolate hetrotrophic bacteria. The reasons may be due to

What amount of dry organic matter is produced by the deep ocean areas?

The diagnostic enzyme for denitrification is

Which of the following organism have siliceous skeletons?

Which of the following product is not obtained from dissimilation of organic matter under aerobic conditions?

Syntrophism involves

Which of the following soil microorganism is involved in the reduction of sulfates to H2S?

Which of the following fungi on infecting crop roots can improve their uptake of phosphorus and other nutrients?

The phenomenon of commensalism refers to a relationship between organisms in which

Hyphomycete fungi

The chief spoilage organisms on smoked fish are

Bacteria, as a group, are responsible for

Which among the following oceans is the most richest in life?

The physical structure of soil is improved by the accumulation of

Marinated (sour pickled) fish should not have spoilage problems unless

The organisms responsible for the characteristic musty or earth odor of a freshly plowed field is/are

Loss of carbon through the microbial loop in oligotrophic environments is __________ to/than the loss of carbon through the microbial loop in copiotrophic environments.

Chemical precipitation of phosphorus is

Which of the following aquatic organisms contribute in a small amount to the shallow estuary food web?

The nonsymbiotic bacteria which fix nitrogen live in the soil independently are

Coliforms are used as indicator organisms because

A heterocyst is

The primary producers in the marine system are ________________

In chilled shrimp __________ is chiefly responsible for spoilage.

The sulfur pearl of Namibia, Thiomargarita namibiensis

The coastal adjunct of the marine ecosystem is __________________

Which of the following techniques can be used to separate different-size fractions of the aquatic microbial community?

Because it can be used with a variety of media and allow a resuscitation step the __________ technique has become the common and often preferred method of evaluating the microbiological characteristics of water.

All of the following species are considered coliforms except

At higher temperatures, the souring of Oysters may be the result of the fermentation of sugars by

Removal of solids is generally considered as a

In which of the following seasons does the nutrient concentration falls at a drastically lower level?

The nitrogenase consists of

Which of the following techniques is used for identification and enumeration of algae, bacteria, protozoa?

Most aquatic microorganisms can grow on the usual laboratory media.

Large spiraling surface currents in the ocean that tend to aggregate and retain nutrients are known as _______________

Phytoplanktonic organisms are non-motile.

The degree of salinity in freshwater is nearly zero.

The microorganisms from lakes and rivers can grow at a salt concentration of _________

The rate of flux of oxygen in air is __________ to/than the rate of flux of oxygen in water.

__________ is an environment like __________ where microorganisms are functioning in an extremely thin film of water and where oxygen-containing air is close to them.

Activated sludge undergoes

Which of the following is a symbiotic nitrogen fixing bacteria?

is an environment like where microorganisms are functioning in an extremely thin film of water and where oxygen-containing air is close to them.