Question 1

Which of the following terms best describes the removal or destruction of ALL living organisms from an object or surface?

Accepted Answer

Sterilization

Question 2

A hospital uses filtration to sterilize heat-sensitive solutions. What is the primary mechanism by which filtration removes bacteria?

Accepted Answer

Separation of bacteria from suspending liquid

Question 3

Which of the following statements about Gram-positive bacteria and disinfection is TRUE?

Accepted Answer

Gram-positive bacteria are generally more sensitive to disinfection than Gram-negative bacteria.

Question 4

A chemical agent is used to kill microorganisms on a surgical instrument. Which term best describes this agent?

Accepted Answer

Disinfectant

Question 5

Which physical method of microbial control is most effective for destroying DNA?

Accepted Answer

Ionizing radiation

Question 6

A microbiologist is culturing obligate anaerobes. Which type of culture medium is required?

Accepted Answer

Reducing medium

Question 7

Which enzyme catalyzes the reaction $$2H_2O_2 \rightarrow 2H_2O + O_2$?

Accepted Answer

Catalase

Question 8

During bacterial growth, which phase is characterized by the accumulation of waste products and a change in pH?

Accepted Answer

Stationary phase

Question 9

A tube of thioglycollate medium shows growth throughout the tube, but most dense at the top. Which type of bacteria is most likely present?

Accepted Answer

Facultative anaerobe

Question 10

Which of the following best describes a fastidious microbe?

Accepted Answer

A microbe that requires many growth factors

Question 11

A patient receives an alcohol pad before an injection. This is an example of which process?

Accepted Answer

Antisepsis

Question 12

Which of the following media is selective for Gram-negative bacteria and differentiates lactose fermenters?

Accepted Answer

MacConkey Agar

Question 13

Which enzyme catalyzes the reaction $$O_2$$^- + $$O_2^- + 2H$$^+ \rightarrow H_2O_2 + $$O_2$$?

Accepted Answer

Superoxide dismutase

Question 14

A microbiologist wants to reduce the microbial count on restaurant glassware to safe public health levels. Which process should be used?

Accepted Answer

Sanitization

Question 15

Which of the following is a chemical used to inhibit microorganisms, but not necessarily kill them?

Accepted Answer

Bacteriostatic agent

Question 16

Which physical method of microbial control involves protein denaturation and is commonly used for milk?

Accepted Answer

Pasteurization

Question 17

Which of the following best describes a chemically defined medium?

Accepted Answer

Exact chemical composition is known

Question 18

Staphylococcus aureus is inoculated into a nutrient medium containing 7.5% NaCl. What does this demonstrate about the organism?

Accepted Answer

It is halotolerant

Question 19

Which of the following is NOT a correct match between the enzyme and its reaction?

Accepted Answer

Catalase: $$O_2$$^- + $$O_2^- + 2H$$^+ \rightarrow H_2O_2 + $$O_2$$

Question 20

A researcher observes that a bacterial culture shows no growth in the presence of oxygen and only grows at the bottom of a thioglycollate tube. What type of organism is this?

Accepted Answer

Obligate anaerobe

Microbial Control, Culture Media, and Bacterial Physiology: Study Notes

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