Question 1

Which of the following best describes Fanny Hesse's contribution to microbiology?

Accepted Answer

She discovered the use of agar as a solidifying agent for culture media.

Question 2

A patient is suspected of having a Helicobacter pylori infection. Which test is most commonly used to detect the presence of H. pylori based on its metabolic activity?

Accepted Answer

Urease breath test

Question 3

Which of the following media is both selective for Gram-negative bacteria and differential based on lactose fermentation?

Accepted Answer

MacConkey agar

Question 4

Staphylococcus aureus is able to grow on human skin due to its ability to tolerate high salt concentrations. Which term best describes this property?

Accepted Answer

Halotolerant

Question 5

A bacterial culture is grown in a chemostat. Which statement best describes the purpose of a chemostat in microbial growth studies?

Accepted Answer

It allows for the continuous removal of waste and addition of fresh nutrients, maintaining cells in exponential phase.

Question 6

Which equation correctly calculates the number of bacteria after $$n$$ generations, starting with $$N_0$$ cells?

Accepted Answer

$$N = N_0$ 	imes 2^n$$

Question 7

Which organism is most likely to grow throughout a thioglycolate broth tube, showing no preference for oxygen?

Accepted Answer

Aerotolerant anaerobe

Question 8

A microbiologist wants to distinguish between bacteria that can hemolyze red blood cells and those that cannot. Which medium should they use?

Accepted Answer

Blood agar

Question 9

Listeria monocytogenes is unique among foodborne pathogens because it can:

Accepted Answer

Grow at refrigeration temperatures

Question 10

Which of the following is a primary metabolite produced during the exponential phase of bacterial growth?

Accepted Answer

Amino acids

Question 11

A student is asked to calculate the number of E. coli cells after 5 generations, starting with 100 cells. Which calculation is correct?

Accepted Answer

$$N = 100 	imes 2^5$ = 3200$$

Question 12

Which of the following best describes the function of selective media?

Accepted Answer

It inhibits the growth of certain organisms while allowing others to grow.

Question 13

Which method is considered an indirect measurement of microbial growth?

Accepted Answer

Measuring turbidity using a spectrophotometer

Question 14

Which of the following is NOT a growth factor required by all bacteria?

Accepted Answer

Glucose

Question 15

Which term describes bacteria that require oxygen for growth and cannot survive without it?

Accepted Answer

Obligate aerobe

Question 16

Which of the following best explains why mannitol salt agar is selective for Staphylococcus species?

Accepted Answer

It contains high salt concentration that inhibits most bacteria except Staphylococcus.

Question 17

Which phase of the bacterial growth curve is characterized by intense metabolic activity but no increase in cell number?

Accepted Answer

Lag phase

Question 18

Which organism would be most likely to survive in a hot spring with temperatures above 70°C?

Accepted Answer

Thermus aquaticus

Question 19

A catalase test is performed on two bacterial isolates. One produces bubbles when hydrogen peroxide is added, the other does not. What does this indicate about the first isolate?

Accepted Answer

It produces catalase and can detoxify reactive oxygen species.

Question 20

Which of the following best describes binary fission in prokaryotes?

Accepted Answer

A process where a single cell divides into two identical daughter cells.

Microbial Growth: Study Guide and Key Concepts (BIO 2350, Ch. 6)

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