Question 1

Organisms that use CO₂ as their source of carbon are called

Accepted Answer

A)   organotrophs.
B)   heterotrophs.
C)   autotrophs.
D)   chemotrophs.
E)   carbonotrophs. C

Question 2

In the cultivation of microaerophilic and anaerobic bacteria,

Accepted Answer

A)   a(n)  candle/anaerobe jar is sufficient.
B)   atmospheric oxygen in a(n)  candle/anaerobe jar is converted to water.
C)   a packet containing chemicals that generate CO₂ and hydrogen is used in a(n)  candle/anaerobic jar.
D)   oxidizing agents are incorporated into the media that react with oxygen.
E)   selective and differential media must always be used.

Question 3

Thayer-Martin agar typically contains a combination of antibiotics: vancomycin, colistin, nystatin, and trimethoprim. Please select the True statement.

Accepted Answer

A)   The antibiotics in Thayer-Martin agar do not kill Gram-negative cells.
B)   The antibiotics in the Thayer-Martin medium lyse the sheep RBCs.
C)   Neisseria gonorrhoeae is not sensitive to the included antibiotics.
D)   Fastidious bacteria are never impacted by common antibiotics.
E)   Sheep blood cell in a growth medium protects bacteria from the impact of antibiotics.

Question 4

It is assumed that every colony observed on a streak plate arose from a single bacterium.

Accepted Answer

A) True 
 B)False

Question 5

Late log phase of the bacterial growth curve

Accepted Answer

A)   is characterized by the production of primary metabolites.
B)   is characterized by the production of secondary metabolites.
C)   is a transition into the death phase.
D)   shows a decline in cell numbers.
E)   is characterized by germination of endospores.

Question 6

What would True about an organism called Bacillus fastidiosus?

Accepted Answer

A)   It might be expected to be very flexible in its growth requirements.
B)   It might be expected to be very strict in its growth requirements.
C)   It could probably be grown on a minimal medium.
D)   It might be expected to have a spherical shape.
E)   It might be expected to depend on sunlight for energy. B

Question 7

A cluster of cases of legionellosis have occurred in your neighborhood. People with the illness have cough, fever, shortness of breath, chest pain and sometimes diarrhea. The illness is caused by the bacterium Legionella pneumophila, a facultative intracellular parasite that survives in certain ameba. The organism has an absolute requirement for L-cysteine.
-In some labs, samples containing suspected L. pneumophila are cultured on traditional BCYE medium as well as BCYE medium lacking L-cysteine. How would L. pneumohila be identified in this situation?

Accepted Answer

A)   Compare the two plates. Colonies that grow on traditional BYCE medium but not on BYCE medium lacking cysteine are likely L. pneumophila.
B)   Compare the two plates. Colonies that grow on BYCE medium lacking cysteine but not on traditional BYCE medium are likely L. pneumophila.
C)   Compare the two plates. Colonies that grow on both traditional BYCE medium and on BYCE medium lacking cysteine are likely L. pneumophila.
D)   Compare the two plates. Colonies that do not grow on traditional BYCE medium or on BYCE medium lacking cysteine, but do grow on nutrient agar are likely L. pneumophila.
E)   Compare the two plates. Colonies that grow on traditional BYCE medium and are blue, yellow or cyan in color are likely L. pneumophila.

Question 8

Organisms that are indifferent to the presence of oxygen and do not use it are

Accepted Answer

A)   aerotolerant anaerobes.
B)   facultative anaerobes.
C)   obligate aerobes.
D)   microaerophiles.
E)   obligate anaerobes.

Question 9

A halophilic, aerobic mesophile has a generation time of 20 minutes. You place 1 × 10⁴ of these organisms on an appropriate solid medium, and incubate the plate for 100 minutes. Select the False statement.

Accepted Answer

A)   The growth medium contains NaCl.
B)   The organism will grow at 40ᵒC. 
C)   After incubation, a colony on the plate contains 3.2 × 10⁵ cells.
D)   After incubation, a colony on the plate contains 5 × 10⁴ cells.
E)   The organism produces superoxide dismutase and catalase.

Question 10

Organisms may derive energy from

Accepted Answer

A)   sunlight AND temperature gradients.
B)   sunlight AND metabolizing chemical compounds.
C)   metabolizing chemical compounds AND temperature gradients.
D)   temperature gradients AND pH gradients.
E)   sunlight AND pH gradients.

Question 11

You are working in a clinical laboratory in a hospital setting. You're handed a throat swab from a patient. You are told specifically that the physician is only interested in the presence and type of Gram positive cells. Identification isn't the main goal here-just a first step to work towards determining what Gram positive cells might be there. What might you do first to go about working towards this goal?

Accepted Answer

A)   Perform a Gram stain.
B)   Streak the sample for isolation on a tryptic soy agar general purpose medium plate.
C)   Streak the sample for isolation on a medium that is selective for Gram positive cells.
D)   Grow the microbes on the swab by inoculating a tryptic soy broth liquid medium tube.
E)   Perform an acid-fast stain.

Question 12

The solidifying agent used most successfully in bacterial nutrient media is

Accepted Answer

A)   gelatin.
B)   peptone.
C)   agar.
D)   starch.
E)   agarose.

Question 13

The simplest technique for isolating bacteria in growth media is referred to as the

Accepted Answer

A)   streak-plate method.
B)   pour-plate method.
C)   serial dilution method.
D)   MPN method.
E)   bacterial growth method.

Question 14

In a rapidly multiplying bacterial population, cell numbers increase

Accepted Answer

A)   arithmetically.
B)   logarithmically.
C)   linearly.
D)   indirectly.
E)   additionally.

Question 15

Bacteria may be stored for several months

Accepted Answer

A)   on a slant in the refrigerator, frozen in agar AND in broth at 37°C.
B)   in broth at 37°C, on a slant in the refrigerator AND frozen in glycerol solution.
C)   on a slant in the refrigerator, frozen in glycerol solution, AND freeze-dried.
D)   freeze-dried, in broth at 37°C AND frozen in agar.
E)   freeze-dried, frozen in glycerol solution AND in broth at 37°C.

Question 16

Secondary metabolites may be antibiotics.

Accepted Answer

A) True 
 B)False

Question 17

During which phase of growth are bacteria most susceptible to antibiotics?

Accepted Answer

A)   Lag
B)   Stationary
C)   Exponential (log) 
D)   Decline
E)   Infection

Question 18

Products that limit pH changes are often incorporated into media and are referred to as

Accepted Answer

A)   enzymes.
B)   buffers.
C)   bases.
D)   acids.
E)   neutrifiers.

Question 19

The lag phase of the bacterial growth curve is marked by

Accepted Answer

A)   a decrease in cell mass.
B)   dormant, metabolically inactive cells.
C)   metabolically active cells.
D)   vigorously dividing cells.
E)   spore-forming cells.

Question 20

Bacteria on fish caught in the Arctic Ocean would

Accepted Answer

A)   be freezophiles AND continue to grow while the fish is in the refrigerator.
B)   be mesophiles AND would continue to grow while the fish is in the refrigerator.
C)   be mesophiles AND would not grow very well in the refrigerator.
D)   be psychrophiles AND would continue to grow while the fish is in the refrigerator.
E)   be thermophiles AND would not grow very well in the refrigerator. D

Exam 4: Dynamics of Microbial Growth

Organisms that use CO₂ as their source of carbon are called

Correct Answer
verified
C

In the cultivation of microaerophilic and anaerobic bacteria,

Correct Answer
verified

Thayer-Martin agar typically contains a combination of antibiotics: vancomycin, colistin, nystatin, and trimethoprim. Please select the True statement.

Correct Answer
verified

It is assumed that every colony observed on a streak plate arose from a single bacterium.

Correct Answer
verified

Late log phase of the bacterial growth curve

Correct Answer
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What would True about an organism called Bacillus fastidiosus?

Correct Answer
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B

Correct Answer
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Organisms that are indifferent to the presence of oxygen and do not use it are

Correct Answer
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A halophilic, aerobic mesophile has a generation time of 20 minutes. You place 1 × 10⁴ of these organisms on an appropriate solid medium, and incubate the plate for 100 minutes. Select the False statement.

Correct Answer
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Organisms may derive energy from

Correct Answer
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Correct Answer
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The solidifying agent used most successfully in bacterial nutrient media is

Correct Answer
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The simplest technique for isolating bacteria in growth media is referred to as the

Correct Answer
verified

In a rapidly multiplying bacterial population, cell numbers increase

Correct Answer
verified

Bacteria may be stored for several months

Correct Answer
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Secondary metabolites may be antibiotics.

Correct Answer
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During which phase of growth are bacteria most susceptible to antibiotics?

Correct Answer
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Products that limit pH changes are often incorporated into media and are referred to as

Correct Answer
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The lag phase of the bacterial growth curve is marked by

Correct Answer
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Bacteria on fish caught in the Arctic Ocean would

Correct Answer
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D

Exam 4: Dynamics of Microbial Growth

Organisms that use CO₂ as their source of carbon are called

Correct AnswerverifiedC

In the cultivation of microaerophilic and anaerobic bacteria,

Correct AnswerverifiedShow Answer

Thayer-Martin agar typically contains a combination of antibiotics: vancomycin, colistin, nystatin, and trimethoprim. Please select the True statement.

Correct AnswerverifiedShow Answer

It is assumed that every colony observed on a streak plate arose from a single bacterium.

Correct AnswerverifiedShow Answer

Late log phase of the bacterial growth curve

Correct AnswerverifiedShow Answer

What would True about an organism called Bacillus fastidiosus?

Correct AnswerverifiedB

Correct AnswerverifiedShow Answer

Organisms that are indifferent to the presence of oxygen and do not use it are

Correct AnswerverifiedShow Answer

A halophilic, aerobic mesophile has a generation time of 20 minutes. You place 1 × 10⁴ of these organisms on an appropriate solid medium, and incubate the plate for 100 minutes. Select the False statement.

Correct AnswerverifiedShow Answer

Organisms may derive energy from

Correct AnswerverifiedShow Answer

Correct AnswerverifiedShow Answer

The solidifying agent used most successfully in bacterial nutrient media is

Correct AnswerverifiedShow Answer

The simplest technique for isolating bacteria in growth media is referred to as the

Correct AnswerverifiedShow Answer

In a rapidly multiplying bacterial population, cell numbers increase

Correct AnswerverifiedShow Answer

Bacteria may be stored for several months

Correct AnswerverifiedShow Answer

Secondary metabolites may be antibiotics.

Correct AnswerverifiedShow Answer

During which phase of growth are bacteria most susceptible to antibiotics?

Correct AnswerverifiedShow Answer

Products that limit pH changes are often incorporated into media and are referred to as

Correct AnswerverifiedShow Answer

The lag phase of the bacterial growth curve is marked by

Correct AnswerverifiedShow Answer

Bacteria on fish caught in the Arctic Ocean would

Correct AnswerverifiedD

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C

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B

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D