1. © Boardworks Ltd 2004 1 of 20 © Boardworks Ltd 2005 1 of 31 Microbes and Disease

2. © Boardworks Ltd 2004 1 of 20 © Boardworks Ltd 2005 2 of 31 Microbes are very small living things and are sometimes called micro-organisms. Microbes are so tiny that they cannot be seen with the naked eye. They can only be seen using a microscope. What are microbes? How many different microbes can you name?

3. © Boardworks Ltd 2004 1 of 20 © Boardworks Ltd 2005 3 of 31 There are different types of microbes: Different types of microbes bacteriaProtists and algae fungi microbes WHAT ARE VIRUSES?

4. © Boardworks Ltd 2004 1 of 20 © Boardworks Ltd 2005 4 of 31 Bacteria fact file size: 1/1000 mm shape: Bacteria can be spherical, rod-shaped or comma-shaped. structure: Bacteria are single- celled organisms. Some cause disease, but many are useful. reproduction: Bacteria reproduce very quickly. They reproduce by splitting in two. Two can very quickly become four, then eight and so on. Bacteria e.g. Salmonella and Streptococcus

5. © Boardworks Ltd 2004 1 of 20 © Boardworks Ltd 2005 5 of 31 Fungi fact file size: Some fungi can actually be seen with the naked eye, others are slightly bigger than bacterial cells. shape: Fungi come in many different shapes. Most fungi are a tangle of thin threads called hyphae. Others have no hyphae. They are yeasts. structure: Fungi have the most complex structures of all the microbes. They feed off other living things. Fungi e.g. Penicillium and yeast

6. © Boardworks Ltd 2004 1 of 20 © Boardworks Ltd 2005 6 of 31 Protists and algae If pond water is seen under microscope, many tiny living organisms can be seen in the water. Tiny plant like are called algae, can make their own food like plants do. Some of them are single celled animals like Protozoa, they feed on other organisms or take nutrients from surroundings

7. © Boardworks Ltd 2004 1 of 20 © Boardworks Ltd 2005 7 of 31 Viruses – are they microorganisms? size: 1/1,000,000 mm shape: Viruses have regular and geometric shapes. structure: A virus does not display ALL the characteristics of living things. reproduction: Viruses can only grow and reproduce within other living things, which is the only characteristic of living organism Viruses e.g. flu virus and HIV (the AIDS virus)

8. © Boardworks Ltd 2004 1 of 20 © Boardworks Ltd 2005 8 of 31 Microbes and Disease Contents What are microbes? Uses of microbes Summary activities Fighting disease How microbes cause disease

9. © Boardworks Ltd 2004 1 of 20 © Boardworks Ltd 2005 9 of 31 Microbes have many uses that are based on the fact that microbes can be grown. Fungi such as yeast in making bread. Bacteria grow in milk to make it ‘go off’. This type of bacterial growth is used to make milk into yogurt. Cheese is another product that is made from milk. Using microbes – bacteria and fungi

10. © Boardworks Ltd 2004 1 of 20 © Boardworks Ltd 2005 10 of 31 The diseases caused by microbes and their severity depend on the type of microbe. viruses bacteria influenza (flu)food poisoning mumpssore throats chickenpoxtuberculosis (TB) smallpoxtetanus poliocholera rabiestyphoid measleswhooping cough fungi fungal sinusitis athlete’s foot discolored toe nails viral meningitis bacterial meningitis Microbes can cause disease

11. © Boardworks Ltd 2004 1 of 20 © Boardworks Ltd 2005 11 of 31 The spreading of microbes and disease is known as transmission. How are microbes spread? A cough or a sneeze can release millions of microbes into the air which can then infect somebody else. 1. Transmission by air Dirty water can transmit many diseases, e.g. cholera, which can be transmitted by drinking. 2. Transmission by water

12. © Boardworks Ltd 2004 1 of 20 © Boardworks Ltd 2005 12 of 31 How are microbes spread? An animal can carry a microbe from one place to another, e.g. a mosquito which spreads the malaria parasite. 3. Transmission by animals Many microbes can be exchanged from one person to another by direct or indirect contact: 4. Transmission by contact direct contact by hand; indirect contact, e.g. by walking on a wet floor already contaminated by someone else who has athlete’s foot;