Question 1

Which of the following best describes the process of microbial growth?

Accepted Answer

An increase in a population of microbes due to reproduction.

Question 2

Which of the following nutrients is NOT commonly required for microbial growth?

Accepted Answer

Calcium

Question 3

A bacterium that can only grow in the absence of oxygen is classified as a(n):

Accepted Answer

Obligate anaerobe

Question 4

Which of the following statements about biofilms is correct?

Accepted Answer

Biofilms are communities of microbes attached to a surface and encased in a self-produced matrix.

Question 5

Which of the following best explains why obligate anaerobes are killed by oxygen?

Accepted Answer

They lack enzymes such as superoxide dismutase and catalase to detoxify reactive oxygen species.

Question 6

A microbe that grows best at a pH of 3.0 would be classified as a(n):

Accepted Answer

Acidophile

Question 7

Which of the following is a direct method for measuring microbial growth?

Accepted Answer

Counting colonies on a plate after serial dilution

Question 8

Which of the following best describes a facultative anaerobe?

Accepted Answer

It can grow with or without oxygen but grows better with oxygen.

Question 9

Which of the following equations correctly represents the exponential growth of a bacterial population?

Accepted Answer

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

Question 10

A culture medium that contains beef extract, peptone, and agar is best described as:

Accepted Answer

A complex medium

Question 11

Which of the following is a reason why biofilms are clinically significant?

Accepted Answer

Biofilms protect microbes from the immune system and increase resistance to antibiotics.

Question 12

Which of the following best describes the lag phase of a bacterial growth curve?

Accepted Answer

Cells are adjusting to a new environment and not dividing rapidly.

Question 13

Which of the following is NOT a function of culture media in microbiology?

Accepted Answer

Serving as a source of antibiotics to kill microbes

Question 14

A microbiologist wants to isolate a single bacterial species from a mixed sample. Which technique should they use?

Accepted Answer

Streak plate method

Question 15

Which of the following statements about anaerobic culture techniques is correct?

Accepted Answer

Anaerobic chambers are used to exclude oxygen and allow growth of obligate anaerobes.

Question 16

Which of the following best describes the stationary phase of a bacterial growth curve?

Accepted Answer

The rate of cell division equals the rate of cell death.

Question 17

Which of the following is a reason why agar is used as a solidifying agent in culture media?

Accepted Answer

It remains solid at incubation temperatures and is not degraded by most microbes.

Question 18

Which of the following best describes a selective medium?

Accepted Answer

A medium that inhibits the growth of some microbes while allowing others to grow.

Question 19

Which of the following is a common method for preserving bacterial cultures for long-term storage?

Accepted Answer

Deep freezing

Question 20

A microbiologist is measuring the turbidity of a bacterial culture using a spectrophotometer. Which of the following best describes what is being measured?

Accepted Answer

The cloudiness of the culture, which correlates with cell density

Chapter 6 Microbiology - Microbial Nutrition and Growth

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