AP-Micro Microbiology: Laboratory Operations and Safety 2

Question 1

Which biosafety cabinet (BSC) class provides personnel protection only and does NOT protect the product from contamination?

Accepted Answer

Class I

Answer

Class II Type A2

Answer

Class II Type B2

Answer

Class III

Question 2

A technician must dispose of a culture plate containing a BSL-2 organism. What is the correct first step before placing it in the biohazard waste bag?

Accepted Answer

Autoclave the plate at 121°C for at least 15 minutes

Answer

Spray the plate surface with 70% ethanol

Answer

Seal the plate with Parafilm and label it

Answer

Place it directly in a sharps container

Question 3

When calibrating a micropipette, which technique produces the most accurate volume delivery for aqueous solutions?

Accepted Answer

Air displacement with a pre-wet tip

Answer

Forward pipetting

Answer

Reverse pipetting

Answer

Positive displacement

Question 4

The use of personal protective equipment (PPE) is governed by the hierarchy of controls. Where does PPE fall in this hierarchy?

Accepted Answer

Last line of defense

Answer

Elimination

Answer

Engineering controls

Answer

Administrative controls

Question 5

A researcher accidentally spills a small volume of a BSL-2 culture on the bench. What is the correct immediate action?

Accepted Answer

Cover with paper towels soaked in 10% bleach for 20 minutes, then clean up

Answer

Immediately wipe up with dry paper towels and discard

Answer

Turn on the UV lamp for 30 minutes to decontaminate the area

Answer

Evacuate the lab and call emergency services

Question 6

Which type of culture media allows any organism to grow without providing any selective advantage or differential characteristic?

Accepted Answer

General-purpose (non-selective) media

Answer

Selective media

Answer

Differential media

Answer

Enrichment media

Question 7

During an aseptic transfer, why must the loop or needle be flamed to red-hot before and after each transfer?

Accepted Answer

To sterilize the loop and prevent cross-contamination between cultures

Answer

To activate the growth factors on the loop surface

Answer

To ensure the agar surface is dry before inoculation

Answer

To destroy the handle plastic to prevent reuse