FREE AP-MICRO Laboratory Operations and Safety Questions and Answers

Question 1

A new trainee in a microbiology laboratory is observed performing several tasks.
Which of the following actions requires immediate correction by the training supervisor due to the significant risk of creating infectious aerosols?

Accepted Answer

Forcefully expelling the last drop of liquid from a pipette into a culture medium.

Answer

Gently mixing a capped tube of broth culture on a vortex mixer.

Answer

Using a sterile loop to transfer colonies from an agar plate to a broth tube.

Answer

Taping a culture plate shut before placing it in the incubator.

Question 2

A reference laboratory needs to ship a pure culture of *Bacillus anthracis* to the CDC for further testing. According to IATA/DOT shipping regulations, this organism must be classified and shipped as:

Accepted Answer

A Category A Infectious Substance, UN 2814.

Answer

An exempt patient specimen.

Answer

A Category B Infectious Substance, UN 3373.

Answer

Biological product, n.o.s.

Question 3

A technologist accidentally drops and breaks a flask containing a liquid culture of *Mycobacterium tuberculosis* outside the biosafety cabinet. Which of the following is the most critical first step in the cleanup procedure?

Accepted Answer

Alert others, vacate the area immediately, and prevent re-entry for at least 30 minutes.

Answer

Immediately wipe up the spill with paper towels and discard in the regular trash.

Answer

Cover the spill with paper towels and carefully pour 70% ethanol over them.

Answer

Pour concentrated bleach directly onto the spill and let it sit for 5 minutes.

Question 4

A technologist needs to subculture a mold isolate that is highly suspicious for *Coccidioides immitis*. To minimize the risk of laboratory-acquired infection, this work must be performed in which of the following?

Accepted Answer

A Class II Biosafety Cabinet.

Answer

A chemical fume hood.

Answer

A horizontal laminar flow clean bench.

Answer

On an open bench with a respirator.

Question 5

Which set of parameters is most commonly used for routine steam sterilization of microbiological media and decontamination of biohazardous waste in an autoclave?

Accepted Answer

121°C for 15 minutes at 15 psi.

Answer

100°C for 30 minutes at 5 psi.

Answer

134°C for 5 minutes at 30 psi.

Answer

160°C for 2 hours (dry heat).

Question 6

A laboratory technologist is preparing a disinfectant solution for the daily cleaning of a countertop where routine bacterial cultures are processed. What is the recommended dilution of household bleach (5.25-6.25% sodium hypochlorite) for use as a general-purpose laboratory disinfectant?

Accepted Answer

1:10 dilution

Answer

1:100 dilution

Answer

Undiluted

Answer

1:50 dilution

A new trainee in a microbiology laboratory is observed performing several tasks.Which of the following actions requires immediate correction by the training supervisor due to the significant risk of creating infectious aerosols?

A new trainee in a microbiology laboratory is observed performing several tasks.
Which of the following actions requires immediate correction by the training supervisor due to the significant risk of creating infectious aerosols?