aseptic technique Flashcards
(11 cards)
How do you transfer bacteria from broth to an agar plate?
Use a sterile pipette or wire hoop to transfer bacteria onto the agar plate
How should bacteria be spread on the agar plate?
Spread bacteria evenly over the plate using a sterile spreader.
How do you place the antibiotic disc on the agar plate?
Use sterile forceps and hold the centre of the disc, not the arms, to place it on the plate
Why do we wipe down surfaces before and after the experiment?
To kill any bacteria present and prevent contamination of the experiment.
Why is a Bunsen burner used in the workspace during aseptic technique?
It creates convection currents that draw microbes away from the working area.
Why do we flame the wire hoop before transferring bacteria?
To sterilise it and kill any unwanted microbes.
Why do we flame the neck of bottles before using them?
To kill microbes around the opening and force air out, preventing contamination.
How do you measure the effectiveness of an antibiotic on an agar plate?
Measure the diameter of the inhibition zone (the clear circle where bacteria didn’t grow).
What does a large inhibition zone mean?
It means the antibiotic has killed more bacteria — the larger the zone, the more effective the antibiotic is
What does a small or no inhibition zone mean?
It shows the bacteria are resistant to the antibiotic and it has little or no effect.
How is antibiotic effectiveness assessed in a lab?
By comparing the size of the inhibition zones around each antibiotic disc on the agar plate
