Microbes and Disease 1 of 31 20 Boardworks

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

Contents What are microbes? Uses of microbes How microbes cause disease Fighting disease Summary activities 1 20 2 of 31 © Boardworks Ltd 2005 2004

What are microbes? 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. How many different microbes can you name? 1 20 3 of 31 © Boardworks Ltd 2005 2004

Walk in I have a car that gets 19 mpg (miles per gallon). This isn’t very good and gasoline isn’t cheap…so help me out. Spark plugs = Plug wires = Air in tires = Air filter = Fuel filter = Transmission fluid = Fuel cleaner = Aerodynamic adjustment = Reduce weight of car = +1 mpg $16 +2 mpg $73 +2 mpg $6 +3 mpg $22 +3 mpg $28 +4 mpg $ 75 +4 mpg $45 +5 mpg $ 90 + 6 mpg $ 180 What is the best way I can spend money to get the most? YOU HAVE 250$ TO WORK WITH! 1 20 4 of 31 © Boardworks Ltd 2005 2004

Different types of microbes There are three types of microbes: microbes bacteria 1 20 5 of 31 viruses fungi © Boardworks Ltd 2005 2004

Bacteria fact file Bacteria e. g. Salmonella and Streptococcus size: 1/1000 mm shape: Bacteria can be spherical, rod-shaped or comma-shaped. structure: Bacteria are singlecelled organisms. Some cause disease, but many are useful. reproduction: Bacteria reproduce very quickly. Two can very quickly become four, then eight and so on. 1 20 6 of 31 © Boardworks Ltd 2005 2004

Viruses fact file Viruses e. g. flu virus and HIV (the AIDS virus) size: 1/1, 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. 1 20 7 of 31 © Boardworks Ltd 2005 2004

Fungi fact file Fungi e. g. Penicillium and yeast 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. structure: Fungi have the most complex structures of all the microbes. They feed off other living things. 1 20 8 of 31 © Boardworks Ltd 2005 2004

Contents Microbes and Disease What are microbes? Uses of microbes How microbes cause disease Fighting disease Summary activities 1 20 9 of 31 © Boardworks Ltd 2005 2004

Using microbes – bacteria and fungi Microbes have many uses that are based on the fact that microbes can be grown. Bacteria grow in milk to make it ‘go off’. l This type of bacterial growth is used to make milk into yogurt. l Cheese is another product that is made from milk. Fungi can also be used to make food. The meat substitute Quorn is a protein produced using fungi. 1 10 ofof 20 31 © Boardworks Ltd 2005 2004

Contents Microbes and Disease What are microbes? Uses of microbes How microbes cause disease Fighting disease Summary activities 1 11 ofof 20 31 © Boardworks Ltd 2005 2004

Microbes can cause disease The diseases caused by microbes and their severity depend on the type of microbe. 1 12 ofof 20 31 viruses bacteria fungi influenza (flu) food poisoning fungal sinusitis mumps sore throats chickenpox tuberculosis (TB) smallpox tetanus athlete’s foot discolored toe nails polio cholera rabies typhoid measles viral meningitis whooping cough bacterial meningitis © Boardworks Ltd 2005 2004

How are microbes spread? The spreading of microbes and disease is known as transmission. 1. Transmission by air A cough or a sneeze can release millions of microbes into the air which can then infect somebody else. 2. Transmission by water Dirty water can transmit many diseases, e. g. cholera, which can be transmitted by drinking. 1 13 ofof 20 31 © Boardworks Ltd 2005 2004

How are microbes spread? 3. Transmission by animals An animal can carry a microbe from one place to another, e. g. a mosquito which spreads the malaria parasite. 4. Transmission by contact Many microbes can be exchanged from one person to another by direct or indirect contact: l direct contact by hand; l indirect contact, e. g. by walking on a wet floor already contaminated by someone else who has athlete’s foot; 1 14 ofof 20 31 © Boardworks Ltd 2005 2004

How is the spread of disease stopped? The spread of disease can be prevented by making sure that good hygiene is used in key places such as bathrooms and kitchens. Chemicals called antibiotics can be used to treat bacterial infections. People can be immunized against some diseases by the injection of a vaccine. 1 15 ofof 20 31 © Boardworks Ltd 2005 2004

Contents Microbes and Disease What are microbes? Uses of microbes How microbes cause disease Fighting disease Summary activities 1 16 ofof 20 31 © Boardworks Ltd 2005 2004

Fighting microbes How does the body fight off microbes that cause disease? 1 17

What do white blood cells do? The human body has a number of natural defences against microbes. Noses are hairy inside to trap microbes! The body also produces white blood cells to help defend it from microbes. white blood cell Some white blood cells can destroy microbes by engulfing them. 1 18 ofof 20 31 © Boardworks Ltd 2005 2004

White blood cell engulfs microbe – animation 1 19 ofof 20 31 © Boardworks

White blood cell and antibodies – animation 1 20 ofof 20 31 © Boardworks

Contents 8 C Microbes and Disease What are microbes? Uses of microbes How microbes cause disease Fighting disease Summary activities 1 21 ofof 20 31 © Boardworks Ltd 2005 2004

Glossary l antibiotics – Chemicals prescribed as medicine to kill bacteria inside the body. l antibodies – Chemicals produced by white blood cells to fight microbes that cause disease. l bacteria – The type of microbes that are single-celled organisms. l fungi – The type of microbes that feed off other living things. l immune – Resistance to infection caused by a microbe. l microbe – A very small living thing. l transmission – The spread of a disease from person to person. l viruses – The type of microbes that can only grow and reproduce within other living things. 1 22 ofof 20 31 © Boardworks Ltd 2005 2004