Basic Laboratory Equipment Use 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 Basic Laboratory Equipment Use flashcards as text
A spectrophotometer is used to measure the optical density (OD600) of a bacterial culture. What is the purpose of the 'blank' measurement?
Answer: To zero the absorbance against the growth media so only bacterial cell density is measured
Blanking with uninoculated media subtracts the absorbance of the media itself, ensuring the measured absorbance reflects only the bacterial cells in suspension.
Which type of pipette is most appropriate for accurately transferring exactly 15.7 mL of a solution?
Answer: A 20 mL graduated (Mohr) pipette
A graduated (Mohr) pipette allows delivery of any volume within its range by reading the graduated scale, making 15.7 mL achievable with a 20 mL graduated pipette.
Why must you never use a mercury thermometer in a laboratory incubator or water bath?
Answer: If broken, mercury vapor and liquid mercury create serious health and environmental hazards that are difficult to remediate
Mercury is a potent neurotoxin; breakage releases mercury vapor and liquid mercury requiring specialized, costly cleanup and posing serious health risks to laboratory staff.
In a laboratory setting, what is the recommended frequency for cleaning and calibrating pH meters?
Answer: Calibrate with fresh buffers before each use session; clean electrode after each use
pH meters should be calibrated with fresh reference buffers at the start of each use session for accurate results; the glass electrode should be rinsed and stored in storage solution after each use.
A biotechnician needs to confirm media has cooled enough after autoclaving before adding heat-sensitive supplements. Which tool is most appropriate?
Answer: A calibrated digital thermocouple or infrared thermometer
A calibrated digital thermocouple or infrared thermometer provides accurate, non-contact or low-contact temperature measurement suitable for monitoring media cooling safely.
What is the primary safety purpose of a chemical fume hood in a laboratory?
Answer: To protect laboratory workers from inhaling toxic vapors, fumes, and aerosols generated during chemical work
Chemical fume hoods draw air away from the worker and exhaust it outside the building, protecting against inhalation of hazardous vapors, fumes, dust, and aerosols.