Question 1

A culture medium consisting of agar, peptone, and beef heart is a

Accepted Answer

A)   complex medium.
B)   reducing medium.
C)   chemically defined medium.
D)   differential medium.
E)   selective medium.F) C) and D)
G) A) and D)

Question 2

If cells are grown in media containing amino acids labeled with radioactive nitrogen ( 15N) , most of the radioactivity will be found in the cellsʹ

Accepted Answer

A)   phospholipids.
B)   proteins.
C)   DNA.
D)   DNA and proteins.
E)   DNA and phospholipids.F) A) and B)
G) A) and E)

Question 3

A sample of milk is tested for its bacterial content in a plate count assay. A one -milliliter sample of the milk is diluted in a 1:10 dilution series. One milliliter of the third dilution tube is plated in a pour plate. After incubation, the plate has 54 colonies, indicating that the original milk sample contained

Accepted Answer

A)   54,000 cells per milliliter.
B)   540,000 cells per milliliter.
C)   5,400 cells per milliliter.
D)   540 cells per milliliter.
E)   54 cells per milliliter.F) A) and B)
G) B) and D)

Question 4

Which of the following elements is NOT correctly matched with its cellular function?

Accepted Answer

A)   phosphorus - used for production of carbohydrates.
B)   nitrogen - needed for amino acid synthesis
C)   sulfur - used for synthesis of thiamin and biotin
D)   phosphorus - incorporated into nucleic acids
E)   magnesium and potassium - required as cofactors for enzymesF) C) and E)
G) All of the above

Question 5

Most pathogenic bacteria are thermophiles.

Accepted Answer

A) True 
 B)False

Question 6

Which of the following is an advantage of the direct microscopic count?

Accepted Answer

A)   sample volume is unknown
B)   requires no incubation time
C)   can easily distinguish live from dead cells
D)   can readily count organisms that are motile
E)   requires a large number of cellsF) A) and E)
G) A) and C)

Question 7

Assume you inoculated 100 cells, with a generation time of 20 minutes, into 100 ml of nutrient broth. You then inoculated 100 cells of the same species into 200 ml of nutrient broth. After incubation for 4 hours, you can reasonably expect to have

Accepted Answer

A)   more cells in the 100 ml.
B)   more cells in the 200 ml.
C)   the same number of cells in both.
D)   The answer cannot be determined based on the information provided.E) B) and C)
F) A) and C)

Question 8

Which enzyme catalyzes the reaction: H₂O₂ + 2H+ → ₂H₂O?

Accepted Answer

A)   catalase
B)   oxidase
C)   peroxidase
D)   superoxide dismutaseE) A) and D)
F) A) and C)

Question 9

Pathogenic bacteria isolated from the respiratory or intestinal tracts of humans are

Accepted Answer

A)   strict aerobes that grow best in candle jars.
B)   capnophiles that grow best in carbon dioxide incubators.
C)   capnophiles that prefer highly oxygenated growth conditions.
D)   strict aerobes that grow best in reducing media.
E)   facultative anaerobes that require reducing media for growth.F) A) and E)
G) C) and D)

Question 10

Which of the following is an example of a metabolic activity that could be used to measure microbial growth?

Accepted Answer

A)   glucose consumption
B)   most probable number (MPN) 
C)   direct microscopic count
D)   turbidity
E)   standard plate countF) A) and E)
G) B) and C)

Question 11

Patients with indwelling catheters (long-term tubes inserted into body orifices for drainage, such as through the urethra and into the urinary bladder)  are susceptible to infections because

Accepted Answer

A)   bacteria cause infections.
B)   injected solutions are contaminated.
C)   infections can be transmitted from other people.
D)   their immune systems are weakened.
E)   biofilms develop on catheters.F) A) and B)
G) D) and E)

Question 12

Table 6.1
Three different culture media are shown below.
   Medium A  Medium B  Medium C Na2HPO4 Tide detergent  Glucose KH2PO4Na2HPO4 Peptone MgSO4KH2PO4(NH4) 2SO4CaCl2MgSO4KH2KO2NaHCO3(NH4) 2SO4Na2HPO4\begin{array} { | l | l | l | } \hline 	ext { Medium A } & 	ext { Medium B } & 	ext { Medium C } \\hline \mathrm { Na } 2 \mathrm { HPO } 4 & 	ext { Tide detergent } & 	ext { Glucose } \\hline \mathrm { KH } 2 \mathrm { PO } 4 & \mathrm { Na } 2 \mathrm { HPO } 4 & 	ext { Peptone } \\hline \mathrm { MgSO } 4 & \mathrm { KH } 2 \mathrm { PO } 4 & ( \mathrm { NH } 4 )  2 \mathrm { SO } _ { 4 } \\hline \mathrm { CaCl } 2 & \mathrm { MgSO } 4 & \mathrm { KH } 2 \mathrm { KO } _ { 2 } \\hline \mathrm { NaHCO } 3 & ( \mathrm { NH } 4 )  _ { 2 } \mathrm { SO } _ { 4 } & \mathrm { Na } _ { 2 } \mathrm { HPO } _ { 4 } \\hline\end{array} Medium A Na2HPO4KH2PO4MgSO4CaCl2NaHCO3​ Medium B  Tide detergent Na2HPO4KH2PO4MgSO4(NH4) 2​SO4​​ Medium C  Glucose  Peptone (NH4) 2SO4​KH2KO2​Na2​HPO4​​​ 
-In Table, 6.1, in which medium (or media)  would an autotroph grow?

Accepted Answer

A)   A
B)   B
C)   C
D)   A and B
E)   A and C F) None of the above
G) A) and B)

Question 13

In performing a ten-fold dilutions series from a sample containing 10,000 bacteria per milliliter, the fourth tube in the dilution series will have 10 cells per milliliter.

Accepted Answer

A) True 
 B)False

Question 14

Most bacteria grow best at pH

Accepted Answer

A)   7.
B)   1.
C)   5.
D)   14.
E)   9.F) B) and D)
G) B) and C)

Question 15

The term aerotolerant anaerobe refers to an organism that

Accepted Answer

A)   tolerates normal atmospheric nitrogen gas levels.
B)   requires less oxygen than is present in air.
C)   does not use oxygen but tolerates it.
D)   is killed by oxygen.
E)   requires more oxygen than is present in air.F) C) and D)
G) D) and E)

Question 16

During which growth phase will gram-positive bacteria be most susceptible to penicillin?

Accepted Answer

A)   stationary phase
B)   log phase
C)   lag phase
D)   death phase
E)   The culture is equally susceptible during all phases.F) A) and D)
G) A) and E)

Question 17

The source of nutrients in nutrient agar is

Accepted Answer

A)   peptone and beef extract.
B)   peptone and NaCl.
C)   agar.
D)   agar and NaCl.
E)   gelatin.F) D) and E)
G) A) and B)

Question 18

Which enzyme catalyzes the reaction: O₂- + O₂- + 2H+ → H₂O₂ + O₂?

Accepted Answer

A)   catalase
B)   oxidase
C)   peroxidase
D)   superoxide dismutaseE) None of the above
F) C) and D)

Question 19

Most fungi grow best at pH

Accepted Answer

A)   7.
B)   1.
C)   14.
D)   5.
E)   9.F) D) and E)
G) B) and E)

Question 20

Which enzyme catalyzes the reaction: 2H 2O₂ → ₂H₂O + O₂?

Accepted Answer

A)   catalase
B)   oxidase
C)   peroxidase
D)   superoxide dismutaseE) B) and C)
F) B) and D)

Exam 6: Microbial Growth

During which growth phase will gram-positive bacteria be most susceptible to penicillin?

Correct Answer
verified

Which of the following is an example of a metabolic activity that could be used to measure microbial growth?

Correct Answer
verified

Which of the following elements is NOT correctly matched with its cellular function?

Correct Answer
verified

Pathogenic bacteria isolated from the respiratory or intestinal tracts of humans are

Correct Answer
verified

Assume you inoculated 100 cells, with a generation time of 20 minutes, into 100 ml of nutrient broth. You then inoculated 100 cells of the same species into 200 ml of nutrient broth. After incubation for 4 hours, you can reasonably expect to have

Correct Answer
verified

If cells are grown in media containing amino acids labeled with radioactive nitrogen ( 15N) , most of the radioactivity will be found in the cellsʹ

Correct Answer
verified

A culture medium consisting of agar, peptone, and beef heart is a

Correct Answer
verified

Correct Answer
verified

The term aerotolerant anaerobe refers to an organism that

Correct Answer
verified

Which enzyme catalyzes the reaction: 2H 2O₂ → ₂H₂O + O₂?

Correct Answer
verified

In performing a ten-fold dilutions series from a sample containing 10,000 bacteria per milliliter, the fourth tube in the dilution series will have 10 cells per milliliter.

Correct Answer
verified

Correct Answer
verified

Which of the following is an advantage of the direct microscopic count?

Correct Answer
verified

Most bacteria grow best at pH

Correct Answer
verified

Patients with indwelling catheters (long-term tubes inserted into body orifices for drainage, such as through the urethra and into the urinary bladder) are susceptible to infections because

Correct Answer
verified

Which enzyme catalyzes the reaction: O₂- + O₂- + 2H+ → H₂O₂ + O₂?

Correct Answer
verified

The source of nutrients in nutrient agar is

Correct Answer
verified

Most pathogenic bacteria are thermophiles.

Correct Answer
verified

Most fungi grow best at pH

Correct Answer
verified

Which enzyme catalyzes the reaction: H₂O₂ + 2H+ → ₂H₂O?

Correct Answer
verified

Exam 6: Microbial Growth

During which growth phase will gram-positive bacteria be most susceptible to penicillin?

Correct AnswerverifiedShow Answer

Which of the following is an example of a metabolic activity that could be used to measure microbial growth?

Correct AnswerverifiedShow Answer

Which of the following elements is NOT correctly matched with its cellular function?

Correct AnswerverifiedShow Answer

Pathogenic bacteria isolated from the respiratory or intestinal tracts of humans are

Correct AnswerverifiedShow Answer

Assume you inoculated 100 cells, with a generation time of 20 minutes, into 100 ml of nutrient broth. You then inoculated 100 cells of the same species into 200 ml of nutrient broth. After incubation for 4 hours, you can reasonably expect to have

Correct AnswerverifiedShow Answer

If cells are grown in media containing amino acids labeled with radioactive nitrogen ( 15N) , most of the radioactivity will be found in the cellsʹ

Correct AnswerverifiedShow Answer

A culture medium consisting of agar, peptone, and beef heart is a

Correct AnswerverifiedShow Answer

Correct AnswerverifiedShow Answer

The term aerotolerant anaerobe refers to an organism that

Correct AnswerverifiedShow Answer

Which enzyme catalyzes the reaction: 2H 2O₂ → ₂H₂O + O₂?

Correct AnswerverifiedShow Answer

In performing a ten-fold dilutions series from a sample containing 10,000 bacteria per milliliter, the fourth tube in the dilution series will have 10 cells per milliliter.

Correct AnswerverifiedShow Answer

Correct AnswerverifiedShow Answer

Which of the following is an advantage of the direct microscopic count?

Correct AnswerverifiedShow Answer

Most bacteria grow best at pH

Correct AnswerverifiedShow Answer

Patients with indwelling catheters (long-term tubes inserted into body orifices for drainage, such as through the urethra and into the urinary bladder) are susceptible to infections because

Correct AnswerverifiedShow Answer

Which enzyme catalyzes the reaction: O₂- + O₂- + 2H+ → H₂O₂ + O₂?

Correct AnswerverifiedShow Answer

The source of nutrients in nutrient agar is

Correct AnswerverifiedShow Answer

Most pathogenic bacteria are thermophiles.

Correct AnswerverifiedShow Answer

Most fungi grow best at pH

Correct AnswerverifiedShow Answer

Which enzyme catalyzes the reaction: H₂O₂ + 2H+ → ₂H₂O?

Correct AnswerverifiedShow Answer

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