Question 1

Which macronutrient is primarily required for the synthesis of amino acids and nucleic acids in bacterial cells?

Accepted Answer

Nitrogen

Question 2

A microbiologist wants to grow only ampicillin-resistant bacteria from a mixed sample. Which type of media should she use?

Accepted Answer

Selective media

Question 3

Obligate anaerobes are unable to survive in the presence of oxygen because they lack which of the following enzymes?

Accepted Answer

Superoxide dismutase and catalase

Question 4

Which of the following best describes the growth pattern of facultative anaerobes in thioglycollate medium?

Accepted Answer

Growth throughout the tube, with more growth at the top

Question 5

A bacterium isolated from a deep-sea vent grows optimally at 105°C. Which term best describes this organism?

Accepted Answer

Hyperthermophile

Question 6

Which pH range would most likely support the growth of an alkaliphile?

Accepted Answer

$$8-14$$

Question 7

Why does the food industry use high concentrations of salt to preserve foods?

Accepted Answer

Salt creates a hypertonic environment, causing plasmolysis in bacteria

Question 8

Which method of measuring bacterial growth provides a direct count but cannot distinguish between living and dead cells?

Accepted Answer

Petroff-Hauser chamber

Question 9

A researcher wants to keep a bacterial culture in the exponential phase for an extended period. Which device should she use?

Accepted Answer

Chemostat

Question 10

During which phase of the bacterial growth curve are cells most susceptible to antibiotics targeting protein synthesis?

Accepted Answer

Exponential (log) phase

Question 11

Which of the following is a trace element required in minute quantities by bacteria?

Accepted Answer

Copper

Question 12

A bacterial population is in the stationary phase. What is the relationship between cell division and cell death?

Accepted Answer

Cell division equals cell death

Question 13

Which of the following best describes a biofilm?

Accepted Answer

A community of microorganisms attached to a surface and embedded in EPS

Question 14

What is the primary function of quorum sensing in biofilm formation?

Accepted Answer

To coordinate gene expression based on population density

Question 15

Which of the following media would allow you to distinguish between bacteria based on their ability to ferment mannitol?

Accepted Answer

Differential media

Question 16

A bacterium is described as planktonic. What does this mean?

Accepted Answer

It is free-floating in a liquid medium

Question 17

Which of the following microbes would be most likely to grow in a jar of honey, which has a very high sugar concentration?

Accepted Answer

Osmotolerant microbe

Question 18

A bacterial sample is diluted and plated using the spread plate method. After incubation, 50 colonies are counted on a plate inoculated with $$0.1 mL of a$$ $$10^{-4}$$ dilution. What is the original cell concentration (CFU/mL)?

Accepted Answer

$$5 	imes 10$$^{5}$$ CFU/mL

Question 19

Which of the following statements about biofilms is TRUE?

Accepted Answer

Biofilms can form on medical devices and contribute to chronic infections

Question 20

Which of the following best describes the function of a barophile?

Accepted Answer

Requires high barometric pressure to grow

Microbial Growth and Nutrition Study Guide – Step-by-Step Guidance

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