Aseptic Technique and Contamination Flashcards
6 cards from real BACE practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 6 Aseptic Technique and Contamination flashcards as text
What is the primary purpose of a biosafety cabinet (BSC) in a biotechnology laboratory?
Answer: To provide a sterile work environment and protect personnel from biohazards
A biosafety cabinet provides a sterile, HEPA-filtered work area that protects both the samples and the operator from contamination and biohazardous aerosols.
Which of the following actions would most likely introduce contamination into a sterile cell culture flask?
Answer: Briefly resting the culture flask cap on a clean bench surface outside the hood
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.
What does the term 'sterile technique' specifically mean in a laboratory context?
Answer: Preventing any microorganisms from entering a sterile environment or culture
Sterile technique refers to the set of practices used to prevent any microorganisms from contaminating sterile materials, media, cultures, or equipment.
How often should the interior surfaces of a biological safety cabinet be decontaminated with 70% ethanol?
Answer: Before and after each use session
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.
A laboratory technician notices that a cell culture flask contains turbid (cloudy) media that was previously clear. What is the most likely explanation?
Answer: Microbial contamination has occurred in the culture
Sudden turbidity in previously clear culture media is a classic sign of microbial (bacterial or yeast) contamination, which rapidly multiplies and clouds the media.
What is the correct order of operations when beginning work in a biological safety cabinet?
Answer: Turn on blower then wait 5 min for airflow to stabilize then wipe with 70% ethanol then begin work
The BSC blower must be running and airflow must stabilize before work begins; surfaces are then decontaminated with 70% ethanol before introducing materials.