1. Introduction to Microbes

2. What is a microbe?
Some living things are so small that we can only see them with a microscope
These are called micro-organisms or microbes
They include:
Bacteria
Viruses
Fungi

4. Bacteria
Found everywhere – in the air, in the soil, in water, inside living things
Some are useful but some cause diseases such as pneumonia, scarlet fever, and tuberculosis
They are single-celled organisms with a cell wall
Multiply very quickly
Affected by antibiotics

5. Viruses Smallest microbe
Parasites – rely on another organism (the host) for food and to reproduce
Not proper cells – have no nucleus nor cell membrane; a strand of DNA wrapped in a protein coat
NOT affected by antiobiotics
Cause diseases such as influenza, the common cold, measles, chicken pox, and AIDS (HIV)

6. Fungi Larger than viruses Plant-like but have no chlorophyll
Examples include yeast and mould
Can be helpful (yeast makes bread rise) and harmful (athlete’s foot and ringworm)

8. Growing Microbes in the Lab
Like all living things, microbes need food to get their energy
We can grow them in the lab on a special jelly called agar in a Petri dish
Agar jelly contains seaweed
If the bacteria are kept warm, they will multiply very rapidly (bacteria can double in number in 20 minutes!)

9. Why are Steps 4 and 5 so important?2 6 5
Why are Steps 4 and 5 so important? 3 1 4

10. Practical – Growing Bacteria
We will use a control
Needed so we can be sure of the cause; so we can see the difference
Acts as a basis for comparison