1. Microbes

2. Give one, get one...
Turn to your partner, for 3 minutes take turns in giving facts about microbes.

3. Name some micro-organisms you know about...

4. Microbes
Examples of microbes include... Bacteria, Fungi and Viruses. They spread very easily because they grow rapidly and use a wide variety of food sources. But remember they can be useful in making products like cheese, yoghurt, bread and beer.

5. Watch the following clip....
Watch video clip -

6. What precautions should the class have taken when setting up the agar plates?

7. Name the equipment shown below...

8. Did you know that you eat bacteria?? Can you think when?

9. Yoghurt Practical Experiment: Label 2 test tubes A and B.
Half fill each test tube with UHT milk.
Add a spatula of natural yoghurt to tube A.
Add a spatula of boiled and cooled yoghurt to tube B.
Add 20 drops of indicator to each.
Seal with rubber stopper and shake.

10. Yoghurt Production
Yoghurt is formed when bacteria convert lactose into lactic acid.
Lactose Lactic Acid
This causes the milk to curdle and coagulate.
Bacteria: Lactobacillus and Streptococcus

11. Fermenters
Fermenters provide all the things which are needed for cell growth;
- Suitable Temperature
- Oxygen
- pH

12. Problems with Fermenters
As numbers of microorganisms increase;
1. The food is used up.
2. The temperature increases as they respire.
3. Oxygen levels decrease as they respire.
4. As the carbon dioxide levels increase, the pH changes.
5. As waste increases the microorganisms begin to die.
Can you think of any advantages to add?

13. How do microbes grow? Produce a graph to demonstrate. Time (mins)
Number of Cells 1 30 2 60 4 90 8
120 16
150 32
180 64
Produce a graph to demonstrate.