BACE - Biotechnician Assistant Credentialing Aseptic Technique and Contamination Questions and Answers

Question 1

A biotechnician is preparing to work with a mammalian cell culture inside a horizontal laminar flow hood. Which of the following actions is MOST critical to maintaining aseptic conditions?

Accepted Answer

Arranging materials to prevent blocking airflow from the HEPA filter to the critical work area.

Answer

Wiping down all surfaces of the hood with 70% ethanol before and after use.

Answer

Running the hood for at least 15-30 minutes before starting any work.

Answer

Wearing a lab coat, gloves, and safety glasses.

Question 2

During a bacterial transformation procedure, a student flames the mouth of a glass culture tube before and after pipetting a liquid medium. What is the primary purpose of this action?

Accepted Answer

To create an upward convection current that prevents airborne contaminants from entering the tube.

Answer

To warm the glass, preventing it from cracking.

Answer

To kill any microorganisms that may have settled on the lip of the tube.

Answer

To create a vacuum seal when the cap is replaced.

Question 3

Which of the following is considered a source of chemical contamination in a cell culture, rather than biological contamination?

Accepted Answer

Endotoxins from gram-negative bacteria

Answer

Mycoplasma

Answer

Yeast spores

Answer

Cross-contamination from another cell line

Question 4

A technician needs to sterilize a heat-sensitive liquid solution containing a protein that would be denatured by autoclaving. Which method would be most appropriate for this task?

Accepted Answer

Filtration using a 0.22 µm filter

Answer

Dry heat sterilization

Answer

Autoclaving

Answer

Treatment with 70% ethanol

Question 5

While streaking bacteria on an agar plate using a metal inoculation loop, a technician realizes they forgot to flame the loop after the initial streak. What is the MOST likely outcome of this error?

Accepted Answer

There will be excessive, confluent growth across the entire plate instead of isolated colonies.

Answer

The agar plate will remain completely sterile with no growth.

Answer

Only the initial quadrant of the plate will show bacterial growth.

Answer

The bacteria will fail to grow due to overheating.

Question 6

Which of the following is a key principle of aseptic technique designed to maintain the sterility of a work area and culture?

Accepted Answer

Keeping sterile items and cultures open to the air as briefly as possible.

Answer

Working quickly to minimize the time for contamination.

Answer

Using antibiotics in all media to prevent any bacterial growth.

Answer

Pouring media directly from large stock bottles to avoid pipetting errors.

A biotechnician is preparing to work with a mammalian cell culture inside a horizontal laminar flow hood.Which of the following actions is MOST critical to maintaining aseptic conditions?

A biotechnician is preparing to work with a mammalian cell culture inside a horizontal laminar flow hood.
Which of the following actions is MOST critical to maintaining aseptic conditions?