agar prac bio

list aseptic tehcnqiues

• sterilise equipment / surfaces (before use) • (use) sterilised agar •
secure lid of the Petri dish with (adhesive) tape •
only lift lid of Petri dish a little (when setting up plate)
lift lid of Petri dish at an angle (when setting up plate)

how to calc zone of inhibition

pi x r² of the part where no bacteria is growing only

0 2 . 4 Suggest one way the student could improve the investigation.

repeat and calculate mean

use different types of bacteria

what does the larhger the zone mean

more larhger the zone the more effective

• Petri dishes and culture media must be sterilised before use:

• prevent contamination from unwanted microorganisms. introduce harmful bacteria, affecting the reliability of your results.

Inoculating loops used to transfer microorganisms

. Sterilising the loop by passing it through a flame ensures that any microorganisms that may have been left on the loop after the previous use are killed.

The lid of the Petri dish should be secured with adhesive tape and stored upside down:

s prevent the lid from becoming dislodged, which could introduce airborne contaminants to the culture. Storing the Petri dish upside down ensures that any condensation that forms on the lid (which could drip onto the culture) falls away from the media, preventing it from disrupting the growing microorganisms and potentially leading to contamination.

Incubation at 25°C

o reduce the risk of harmful bacterial growth.