Question 1

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

Accepted Answer

The number of new cells equals the number of dying cells, resulting in no net population growth.

Question 2

A hospital is deciding how to sterilize heat-sensitive surgical instruments. Which method would be most appropriate?

Accepted Answer

Filtration through a membrane with pore size $$0.22\ \mu m$$

Question 3

Which of the following statements about antisepsis is correct?

Accepted Answer

It reduces the number of microbes on living tissue to safe levels.

Question 4

A patient is prescribed an antibiotic that inhibits cell wall synthesis. Which of the following best explains how this drug works?

Accepted Answer

It prevents the formation of peptidoglycan, weakening the bacterial cell wall.

Question 5

Which environmental factor would most likely inhibit the growth of an obligate aerobe?

Accepted Answer

Growth in an anaerobic chamber with no oxygen

Question 6

A laboratory technician wants to measure the number of viable bacteria in a sample. Which method should they use?

Accepted Answer

Serial dilution and plating on nutrient agar

Question 7

Which of the following is a broad-spectrum antibiotic?

Accepted Answer

Tetracycline

Question 8

A new disinfectant is tested and found to be less effective at low temperatures and in the presence of organic matter. Which factors are influencing its effectiveness?

Accepted Answer

Environmental conditions and presence of organic matter

Question 9

Which of the following best explains why overuse of antibiotics in agriculture contributes to antibiotic resistance?

Accepted Answer

It selects for resistant bacteria, which can transfer resistance genes to human pathogens.

Question 10

A patient develops a wound infection after surgery. The causative bacterium is resistant to multiple antibiotics. Which mechanism most likely contributed to this resistance?

Accepted Answer

Acquisition of resistance genes through horizontal gene transfer

Question 11

Which metabolic pathway yields the most ATP per glucose molecule in bacteria?

Accepted Answer

Aerobic respiration

Question 12

A microbiologist is culturing a thermophile. Which temperature range should be used for optimal growth?

Accepted Answer

$$50^\circC to$$ $$70^\circC$$

Question 13

Which of the following best describes the mechanism of action of quaternary ammonium compounds?

Accepted Answer

They denature proteins and disrupt cell membranes.

Question 14

A patient is treated with a drug that blocks bacterial ribosomes. What is the most likely effect?

Accepted Answer

Inhibition of protein synthesis

Question 15

Which phase of the bacterial growth curve is characterized by exponential increase in cell number?

Accepted Answer

Log (exponential) phase

Question 16

A laboratory uses the Kirby-Bauer disk diffusion test to assess antibiotic sensitivity. What does a large zone of inhibition around a disk indicate?

Accepted Answer

The bacterium is sensitive to the antibiotic.

Question 17

Which of the following is the best example of sterilization?

Accepted Answer

Using an autoclave to treat surgical instruments at $$121^\circC $$for 15 minutes

Question 18

A food processing plant uses UV radiation to treat surfaces. What is the primary effect of this method on microbes?

Accepted Answer

It damages microbial DNA, preventing replication.

Question 19

Which of the following best explains why some bacteria survive boiling but not autoclaving?

Accepted Answer

Bacterial spores are resistant to boiling but are destroyed by the higher temperature and pressure of autoclaving.

Question 20

A patient is prescribed a narrow-spectrum antibiotic. Which of the following is a likely advantage of this treatment?

Accepted Answer

It is less likely to disrupt the patient's normal microbiota.

Microbial Growth, Control, and Antimicrobial Therapy: Study Notes

Study Guide - Practice Questions

Study Guide - Flashcards