Chapter 7 Bacterial and Archaeal Growth
1) Media containing some ingredients of unknown chemical composition are called ________
media.
A) undefined
B) complex
C) defined
D) synthetic
Answer: B
2) Agar is an excellent solidifying agent for microbiological media because ________.
A) it is not degraded by most microorganisms
B) solid agar remains solid until the temperature is raised to 90°C, and liquid agar remains liquid
if the temperature is lowered to 45°C
C) it is not degraded by most microorganisms and solid agar remains solid until the temperature
is raised to 90°C, and liquid agar remains liquid if the temperature is lowered to 45°C
D) agar provides an excellent source of nutrition for a variety of different microorganisms
Answer: C
3) For surface cultivation of microorganisms, a sulfated polymer called agar can be extracted
from ________ and added to liquid media to solidify it.
A) bacteria
B) animal fat
C) algae
D) fungi
Answer: C
4) A growth medium that favors the growth of some microorganisms but inhibits the growth of
other microorganisms is a ________ medium.
A) selective
B) differential
C) selective and differential
D) neither selective nor differential
Answer: A
5) A growth medium that distinguishes among different groups of bacteria on the basis of their
biological characteristics is called a ________ medium.
A) selective
B) differential
C) enrichment
D) transport
Answer: B
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,6) Mannitol salt agar (MSA) only allows the growth of halophiles (salt-loving microbes);
nonhalophiles will not grow. Among the halophiles, mannitol fermenters will produce acid that
turns the pH indicator yellow; mannitol nonfermenters leave the medium red. Onto MSA you
inoculate a halophilic mannitol fermenter and a halophilic mannitol nonfermenter. In this case,
the medium is acting as (a) ________ medium(s).
A) selective
B) differential
C) selective and differential
D) enrichment
Answer: B
7) Mannitol salt agar (MSA) only allows the growth of halophiles (salt-loving microbes). Among
the halophiles, mannitol fermenters release acid that turns the pH indicator yellow; mannitol
nonfermenters leave the medium red. Onto MSA you inoculate a halophilic mannitol
nonfermenter and a nonhalophilic mannitol nonfermenter. Here the medium acts as a ________
medium.
A) selective
B) differential
C) selective and differential
D) enrichment
Answer: A
8) Mannitol salt agar (MSA) only allows the growth of halophiles (salt-loving microbes). Among
the halophiles, mannitol fermenters release acid that turns the pH indicator yellow; mannitol
nonfermenters leave the medium red. Onto MSA you inoculate a halophilic mannitol fermenter,
a nonhalophilic mannitol fermenter, and a halophilic mannitol nonfermenter. Thus, the medium
is acting as a ________ medium.
A) selective
B) differential
C) selective and differential
D) neither selective nor differential
Answer: C
9) Media in which all components and their concentration are known are called ________ media.
A) transport
B) defined
C) selective
D) enrichment
Answer: B
10) You would like to culture a bacterium that is growing in the lung of a human patient with
pneumonia. Which media would be of most use in culturing this organism?
2
, A) Transport media
B) Mannitol salt agar
C) MacConkey's agar
D) Complex medium supplemented with whole blood
E) None of the choices are correct.
Answer: D
11) All fastidious microorganisms require which of the following for growth?
A) Oxygen
B) Temperatures near normal for the human body
C) Extra nutrients (such as whole blood)
D) Iron
Answer: C
12) A given medium can be either selective or differential but not both.
Answer: FALSE
13) Blood agar is both a differential and enriched medium.
Answer: TRUE
14) Growth media that will support the growth of many different types of microorganisms are
called ________ ________ growth media, whereas those that are supplemented by blood or other
rich nutrient sources in order to support the growth of fastidious organisms are called ________
media.
Answer: general purpose; enriched
15) Which of the following can be used to isolate pure cultures of bacteria from mixtures?
A) Spread plates
B) Streak plates
C) Pour plates
D) All of the choices are correct.
Answer: D
16) Macroscopically visible growths or clusters of microorganisms on solid media are called
________.
Answer: colonies
17) The size and shape of a colony is not useful for identification of a microorganism because
most microorganisms produce colonies that are indistinguishable from one another.
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1) Media containing some ingredients of unknown chemical composition are called ________
media.
A) undefined
B) complex
C) defined
D) synthetic
Answer: B
2) Agar is an excellent solidifying agent for microbiological media because ________.
A) it is not degraded by most microorganisms
B) solid agar remains solid until the temperature is raised to 90°C, and liquid agar remains liquid
if the temperature is lowered to 45°C
C) it is not degraded by most microorganisms and solid agar remains solid until the temperature
is raised to 90°C, and liquid agar remains liquid if the temperature is lowered to 45°C
D) agar provides an excellent source of nutrition for a variety of different microorganisms
Answer: C
3) For surface cultivation of microorganisms, a sulfated polymer called agar can be extracted
from ________ and added to liquid media to solidify it.
A) bacteria
B) animal fat
C) algae
D) fungi
Answer: C
4) A growth medium that favors the growth of some microorganisms but inhibits the growth of
other microorganisms is a ________ medium.
A) selective
B) differential
C) selective and differential
D) neither selective nor differential
Answer: A
5) A growth medium that distinguishes among different groups of bacteria on the basis of their
biological characteristics is called a ________ medium.
A) selective
B) differential
C) enrichment
D) transport
Answer: B
1
,6) Mannitol salt agar (MSA) only allows the growth of halophiles (salt-loving microbes);
nonhalophiles will not grow. Among the halophiles, mannitol fermenters will produce acid that
turns the pH indicator yellow; mannitol nonfermenters leave the medium red. Onto MSA you
inoculate a halophilic mannitol fermenter and a halophilic mannitol nonfermenter. In this case,
the medium is acting as (a) ________ medium(s).
A) selective
B) differential
C) selective and differential
D) enrichment
Answer: B
7) Mannitol salt agar (MSA) only allows the growth of halophiles (salt-loving microbes). Among
the halophiles, mannitol fermenters release acid that turns the pH indicator yellow; mannitol
nonfermenters leave the medium red. Onto MSA you inoculate a halophilic mannitol
nonfermenter and a nonhalophilic mannitol nonfermenter. Here the medium acts as a ________
medium.
A) selective
B) differential
C) selective and differential
D) enrichment
Answer: A
8) Mannitol salt agar (MSA) only allows the growth of halophiles (salt-loving microbes). Among
the halophiles, mannitol fermenters release acid that turns the pH indicator yellow; mannitol
nonfermenters leave the medium red. Onto MSA you inoculate a halophilic mannitol fermenter,
a nonhalophilic mannitol fermenter, and a halophilic mannitol nonfermenter. Thus, the medium
is acting as a ________ medium.
A) selective
B) differential
C) selective and differential
D) neither selective nor differential
Answer: C
9) Media in which all components and their concentration are known are called ________ media.
A) transport
B) defined
C) selective
D) enrichment
Answer: B
10) You would like to culture a bacterium that is growing in the lung of a human patient with
pneumonia. Which media would be of most use in culturing this organism?
2
, A) Transport media
B) Mannitol salt agar
C) MacConkey's agar
D) Complex medium supplemented with whole blood
E) None of the choices are correct.
Answer: D
11) All fastidious microorganisms require which of the following for growth?
A) Oxygen
B) Temperatures near normal for the human body
C) Extra nutrients (such as whole blood)
D) Iron
Answer: C
12) A given medium can be either selective or differential but not both.
Answer: FALSE
13) Blood agar is both a differential and enriched medium.
Answer: TRUE
14) Growth media that will support the growth of many different types of microorganisms are
called ________ ________ growth media, whereas those that are supplemented by blood or other
rich nutrient sources in order to support the growth of fastidious organisms are called ________
media.
Answer: general purpose; enriched
15) Which of the following can be used to isolate pure cultures of bacteria from mixtures?
A) Spread plates
B) Streak plates
C) Pour plates
D) All of the choices are correct.
Answer: D
16) Macroscopically visible growths or clusters of microorganisms on solid media are called
________.
Answer: colonies
17) The size and shape of a colony is not useful for identification of a microorganism because
most microorganisms produce colonies that are indistinguishable from one another.
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