Question 1

A hot tub (with a water temperature of 104°F or 40°C)  would most likely contain

Accepted Answer

A)   psychrophiles.
B)   freezophiles.
C)   mesophiles.
D)   thermophiles.
E)   hyperthermophiles.F) B) and C)
G) A) and E)

Question 2

Shigella species and Salmonella species are classified as facultative anaerobes. You know that given this information, the bacteria in your patient's fecal culture will grow best

Accepted Answer

A)   in the absence of oxygen.
B)   in the presence of oxygen.
C)   at low levels of oxygen.
D)   in high levels of carbon dioxide.
E)   if catalase is added to the medium.F) A) and D)
G) A) and C)

Question 3

During which phase of the bacterial growth curve does the total number of viable (live)  cells decline?

Accepted Answer

A)   Stationary
B)   Lag
C)   Exponential
D)   Death
E)   InfectionF) B) and E)
G) B) and C) D

Question 4

A urine sample with more than 100,000 organisms is considered indicative of infection. A urine sample containing 5,000 bacteria, with a generation time of 30 minutes, sits for 3 hours before finally being assayed. How many bacteria will then be present within the sample?

Accepted Answer

A)   320,000
B)   100,000
C)   64,000
D)   15,000
E)   10,000F) C) and D)
G) B) and D)

Question 5

During which phase of the bacterial growth curve does a bacterial population become much more resistant to harmful conditions?

Accepted Answer

A)   Lag phase
B)   Exponential phase
C)   Stationary phase
D)   Late log phase
E)   Decline phaseF) None of the above
G) B) and E)

Question 6

You are a microbiologist working for a pharmaceutical company and discover a new secreted metabolite that can serve as a medication. Your company asks you to oversee the production of the metabolite. Which of the following does NOT need to be considered if you need to grow 5,000 liter cultures of bacteria for the purpose of harvesting the metabolite they secrete?

Accepted Answer

A)   The death rate of the bacteria after stationary phase is complete.
B)   The ideal rate of input of new nutrients into the culture to maintain the cells in log phase.
C)   The ideal rate of pulling off some of the culture in order to maintain the cells in log phase.
D)   The best way to mix the large vat in order to keep nutrient levels, temperature, and oxygen levels constant.
E)   The best way to keep the pH of the entire mixture at the ideal level to promote log phase growth.F) A) and E)
G) A) and C)

Question 7

A modification of the BCYE medium used to culture L. pneumophila is BCYE with DGVP. This medium contains glycine, polymixin B (an antifungal agent) , and and vancomycin (antibiotic) , as well as two dyes (bromocreson purple and bromthymol blue)  that facilitate identification of the organism based on colony color. What type of medium is BCYE with DGVP?

Accepted Answer

A)   Selective
B)   Differential
C)   Selective AND differential
D)   Liquid
E)   AnaerobicF) D) and E)
G) A) and B) C

Question 8

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.F) B) and E)
G) A) and D)

Question 9

Clostridium paradoxum grows optimally at 55°C, pH 9.3; it will not grow in the presence of O2. Please select the TRUE statement about this organism.

Accepted Answer

A)   It is spherical in shape.
B)   It is a psychrophile.
C)   It is an obligate anaerobe.
D)   It is an acidophile.
E)   It is an aerotolerant anaerobe.F) D) and E)
G) A) and E)

Question 10

You are culturing a new bacterium in the laboratory. You cannot find any glucose it the lab when you are making growth medium, so you decide to use honey instead. You add twice as much honey than is called for in the medium recipe, because you want to give the organism the best opportunity or growth. To your surprise, the organism does not grow on your modified medium. Select the most likely explanation.

Accepted Answer

A)   The growth medium became hypotonic with the addition of so much honey; the bacteria underwent plasmolysis and died.
B)   The growth medium became hypertonic with the addition of so much honey; the bacteria underwent plasmolysis and died.
C)   The growth medium became halophilic with the addition of so much honey; the bacteria underwent plasmolysis and died.
D)   The growth medium became hypertonic with the addition of so much honey; the bacteria underwent osmotic lysis and died.
E)   The growth medium became hypotonic with the addition of so much honey; the bacteria underwent simple diffusion and burst.F) C) and D)
G) A) and B)

Question 11

Prokaryotes are the only organisms able to use atmospheric nitrogen as a nitrogen source.

Accepted Answer

A) True 
 B)False

Question 12

Freezing is an effective means of destroying bacteria.

Accepted Answer

A) True 
 B)False

Question 13

Prokaryotic cells divide by a process known as

Accepted Answer

A)   conjugation.
B)   mitosis.
C)   binary fusion.
D)   binary fission.
E)   meiosis.F) C) and D)
G) A) and E)

Question 14

In the growth curve of a bacteria population, the bacteria are rapidly increasing in number in the

Accepted Answer

A)   lag phase.
B)   exponential (log)  phase.
C)   stationary phase.
D)   decline phase.
E)   death phase.F) A) and C)
G) A) and B)

Question 15

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.F) B) and D)
G) C) and D) B

Question 16

The prefix photo- indicates that an organism will make use of ________ for energy purposes.

Accepted Answer

A)   chemicals
B)   organics
C)   light
D)   inorganics
E)   waterF) A) and B)
G) A) and C)

Question 17

Peptone

Accepted Answer

A)   refers to a hydrolysate of carbohydrates used in growth media.
B)   refers to a hydrolysate of proteins used in growth media.
C)   consists of a water extract of beef.
D)   consists of a mix of monosaccharides and oligosaccharides.
E)   refers to a hydrolysate of proteins used in growth media AND consists of a water extract of beef.F) C) and D)
G) A) and C)

Question 18

The solidifying agent used most successfully in bacterial nutrient media is

Accepted Answer

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

Question 19

Organisms that use CO2 as their source of carbon are called

Accepted Answer

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

Question 20

A medium that inhibits the growth of organisms other than the one being sought is called a(n)

Accepted Answer

A)   synthetic medium.
B)   specific culture medium.
C)   selective medium.
D)   enrichment medium.
E)   differential medium.F) C) and D)
G) A) and B)

Exam 4: Dynamics of Microbial Growth

A hot tub (with a water temperature of 104°F or 40°C) would most likely contain

Correct Answer
verified

Shigella species and Salmonella species are classified as facultative anaerobes. You know that given this information, the bacteria in your patient's fecal culture will grow best

Correct Answer
verified

During which phase of the bacterial growth curve does the total number of viable (live) cells decline?

Correct Answer
verified
D

A urine sample with more than 100,000 organisms is considered indicative of infection. A urine sample containing 5,000 bacteria, with a generation time of 30 minutes, sits for 3 hours before finally being assayed. How many bacteria will then be present within the sample?

Correct Answer
verified

During which phase of the bacterial growth curve does a bacterial population become much more resistant to harmful conditions?

Correct Answer
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Correct Answer
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C

In the cultivation of microaerophilic and anaerobic bacteria,

Correct Answer
verified

Clostridium paradoxum grows optimally at 55°C, pH 9.3; it will not grow in the presence of O2. Please select the TRUE statement about this organism.

Correct Answer
verified

Correct Answer
verified

Prokaryotes are the only organisms able to use atmospheric nitrogen as a nitrogen source.

Correct Answer
verified

Freezing is an effective means of destroying bacteria.

Correct Answer
verified

Prokaryotic cells divide by a process known as

Correct Answer
verified

In the growth curve of a bacteria population, the bacteria are rapidly increasing in number in the

Correct Answer
verified

Late log phase of the bacterial growth curve

Correct Answer
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B

The prefix photo- indicates that an organism will make use of ________ for energy purposes.

Correct Answer
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Peptone

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

Correct Answer
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Organisms that use CO2 as their source of carbon are called

Correct Answer
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A medium that inhibits the growth of organisms other than the one being sought is called a(n)

Correct Answer
verified

Exam 4: Dynamics of Microbial Growth

A hot tub (with a water temperature of 104°F or 40°C) would most likely contain

Correct AnswerverifiedShow Answer

Shigella species and Salmonella species are classified as facultative anaerobes. You know that given this information, the bacteria in your patient's fecal culture will grow best

Correct AnswerverifiedShow Answer

During which phase of the bacterial growth curve does the total number of viable (live) cells decline?

Correct AnswerverifiedD

A urine sample with more than 100,000 organisms is considered indicative of infection. A urine sample containing 5,000 bacteria, with a generation time of 30 minutes, sits for 3 hours before finally being assayed. How many bacteria will then be present within the sample?

Correct AnswerverifiedShow Answer

During which phase of the bacterial growth curve does a bacterial population become much more resistant to harmful conditions?

Correct AnswerverifiedShow Answer

Correct AnswerverifiedShow Answer

Correct AnswerverifiedC

In the cultivation of microaerophilic and anaerobic bacteria,

Correct AnswerverifiedShow Answer

Clostridium paradoxum grows optimally at 55°C, pH 9.3; it will not grow in the presence of O2. Please select the TRUE statement about this organism.

Correct AnswerverifiedShow Answer

Correct AnswerverifiedShow Answer

Prokaryotes are the only organisms able to use atmospheric nitrogen as a nitrogen source.

Correct AnswerverifiedShow Answer

Freezing is an effective means of destroying bacteria.

Correct AnswerverifiedShow Answer

Prokaryotic cells divide by a process known as

Correct AnswerverifiedShow Answer

In the growth curve of a bacteria population, the bacteria are rapidly increasing in number in the

Correct AnswerverifiedShow Answer

Late log phase of the bacterial growth curve

Correct AnswerverifiedB

The prefix photo- indicates that an organism will make use of ________ for energy purposes.

Correct AnswerverifiedShow Answer

Peptone

Correct AnswerverifiedShow Answer

The solidifying agent used most successfully in bacterial nutrient media is

Correct AnswerverifiedShow Answer

Organisms that use CO2 as their source of carbon are called

Correct AnswerverifiedShow Answer

A medium that inhibits the growth of organisms other than the one being sought is called a(n)

Correct AnswerverifiedShow Answer

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D

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C

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B

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