BACE Aseptic Technique and Contamination 2

Question 1

What is the primary purpose of a biosafety cabinet (BSC) in a biotechnology laboratory?

Accepted Answer

To provide a sterile work environment and protect personnel from biohazards

Answer

A biosafety cabinet provides a sterile, HEPA-filtered work area that protects both the samples and the operator from contamination and biohazardous aerosols.

Question 2

Which of the following actions would most likely introduce contamination into a sterile cell culture flask?

Accepted Answer

Briefly resting the culture flask cap on a clean bench surface outside the hood

Answer

Placing a culture flask cap on an external bench surface exposes it to environmental microorganisms, which can then contaminate the culture when the cap is replaced.

Question 3

What does the term 'sterile technique' specifically mean in a laboratory context?

Accepted Answer

Preventing any microorganisms from entering a sterile environment or culture

Answer

Sterile technique refers to the set of practices used to prevent any microorganisms from contaminating sterile materials, media, cultures, or equipment.

Question 4

How often should the interior surfaces of a biological safety cabinet be decontaminated with 70% ethanol?

Accepted Answer

Before and after each use session

Answer

BSC interior surfaces should be wiped with 70% ethanol before starting work and again after completing work to ensure the work surface remains free of contamination.

Question 5

A laboratory technician notices that a cell culture flask contains turbid (cloudy) media that was previously clear. What is the most likely explanation?

Accepted Answer

Microbial contamination has occurred in the culture

Answer

Sudden turbidity in previously clear culture media is a classic sign of microbial (bacterial or yeast) contamination, which rapidly multiplies and clouds the media.

BACE - Biotechnician Assistant Credentialing Exam Practice Test

BACE - Biotechnician Assistant Credentialing Exam Practice Test

BACE Aseptic Technique and Contamination 2