Page 204 - Big Ideas Year 10 sciPAD 2025
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204 SCIPAD - BIG IDEAS - BOOK 2
LIFE OF MICROBES
Observing Bacteria and Fungi
An agar plate is a petri dish that contains a jelly-like, nutrient-rich growth medium that can be used
to culture bacteria and fungi. In this investigation you will be culturing microbes on an agar plate.
Aim: To culture and observe bacterial and fungal colonies.
Equipment: 2 x Agar plates Cotton swabs Incubator Adhesive tape
Method: 1. Rub the cotton swab on a lab bench in order to collect microbes. Do not swab from
your body.
2. Lift the lid of one agar plate just enough to get the cotton swab inside. Gently wipe
the cotton swab on the surface of the agar, being careful not to scratch the agar.
3. Replace the lid of the petri dish and label with “inoculated” and your name.
4. Label the unopened agar plate with “uninoculated” and your name.
5. Place both petri dishes upside down in the incubator. It is important they are placed
in upside down so any condensation that forms does not fall onto the agar and
affect the microbes.
6. Leave in the incubator for 24 - 48 hours.
7. Remove the agar plates and observe the bacterial and fungal colonies. Sketch the
colonies in the space provided below.
8. Dispose of your agar plates appropriately. Ideally, they should be incinerated.
Observations:
Dispose of
agar plates
appropriately
Do not open
inoculated agar
plates
Inoculated Plate Uninoculated Plate
Conclusion: Describe the appearance of any bacterial colonies:
Describe the appearance of any fungal colonies:
1. Describe the purpose of the uninoculated plate.
2. Outline why agar plates are stored upside down inside an incubator.
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