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

To store hazardous chemicals safely

Answer

To incubate cell cultures at controlled temperatures

Answer

To centrifuge biological samples at high speed

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

Working inside a laminar flow hood

Answer

Flaming the neck of a glass flask before pouring

Answer

Using sterile disposable pipettes

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

Wearing gloves and a lab coat

Answer

Cleaning benches with 70% ethanol before work

Answer

Autoclaving all solutions used in experiments

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

Only when visibly soiled

Answer

Once per week regardless of use

Answer

Once per month during scheduled maintenance

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

The cells are growing normally and have reached confluence

Answer

The media pH has shifted due to CO2 levels

Answer

The cells have differentiated into a new cell type

Question 6

What is the correct order of operations when beginning work in a biological safety cabinet?

Accepted Answer

Turn on blower then wait 5 min for airflow to stabilize then wipe with 70% ethanol then begin work

Answer

Load materials then turn on blower then wait 5 min then begin work

Answer

Wipe with ethanol then turn on blower then immediately begin work

Answer

Turn on UV light then turn on blower then begin work immediately