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Boardworks KS3 Science 2008 Microbes and Disease

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Presentation on theme: "Boardworks KS3 Science 2008 Microbes and Disease"— Presentation transcript:

1 Boardworks KS3 Science 2008 Microbes and Disease

2 Boardworks KS3 Science 2008 Microbes and Disease
What are microbes?

3 Boardworks KS3 Science 2008 Microbes and Disease
What are microbes? Boardworks KS3 Science 2008 Microbes and Disease 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?

4 Different types of microbes
Boardworks KS3 Science 2008 Microbes and Disease There are three types of microbes: bacteria viruses fungi

5 Boardworks KS3 Science 2008 Microbes and Disease
Bacteria fact file Boardworks KS3 Science 2008 Microbes and Disease Microbe: Bacteria (e.g. salmonella and streptococcus) Size: 1/1000 mm Shape: Bacteria can be spherical, rod-shaped or comma-shaped. Structure: Bacteria are single-celled organisms. Their genetic material is not contained within a nucleus. Some cause disease, but many are useful. Reproduction: Bacteria reproduce very quickly. Two can very quickly become four, then eight and so on.

6 Structure of a bacterium
Boardworks KS3 Science 2008 Microbes and Disease

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How do bacteria divide? Boardworks KS3 Science 2008 Microbes and Disease Video credit: Oxford Scientific (OSF)

8 Boardworks KS3 Science 2008 Microbes and Disease
Virus fact file Boardworks KS3 Science 2008 Microbes and Disease Microbe: Virus (e.g. flu virus and HIV) Size: 1/1,000,000 mm Shape: Viruses have regular and geometric shapes. Structure: A virus is a simple organism that does not display all the characteristics of a living thing. It is made up of a protein coating and some genetic material. Reproduction: Viruses can only grow and reproduce within other living things. Viruses change and adapt to their environment very quickly.

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Structure of a virus Boardworks KS3 Science 2008 Microbes and Disease

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Fungi fact file Boardworks KS3 Science 2008 Microbes and Disease Microbe: 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.

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Structure of a fungus Boardworks KS3 Science 2008 Microbes and Disease

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Looking at microbes Boardworks KS3 Science 2008 Microbes and Disease Photo credit (bacteria): Eye of Science / Science Photo Library Klebsiella pneumoniae bacteria, light micrograph. These are Gram-negative rod-shaped (bacillus) bacteria that are usually found in the intestines of healthy individuals. However, in those with a weakened immune system K. pneumoniae can cause a number of infections. It most commonly causes hospital-acquired urinary tract or open wound infections, but can also cause pneumonia. Magnification: x500 when printed at 10 centimetres wide. Photo credit (fungi): Herve Conge, ISM / Science Photo Library Brewer's yeast (Saccharomyces cerevisiae), light micrograph using differential interference contrast illumination. This is a single-celled fungus that is widely used for brewing and baking, due to its ability to ferment sugars into carbon dioxide and ethanol (alcohol). Magnification: x1100 when printed 10cm wide. Photo credit (virus): Eye of Science / Science Photo Library Coloured transmission electron micrograph (TEM) of HIV (human immunodeficiency virus), which causes AIDS (acquired immune deficiency syndrome). The virus consists of a RNA (ribonucleic acid) genome, surrounded by an icosahedral (20-sided) protein nucleocapsid (coat). This is enclosed in a matrix of proteins and the whole virus is enclosed in an envelope derived from the host cell's plasma membrane. The envelope has viral proteins integrated into it, including glycoprotein spikes that aid attachment to host cells. HIV infects the immune system's T-lymphocytes, ultimately killing them, leading to a very weak immune system. Magnification: x when printed 10 centimetres wide.

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Uses of microbes

14 Using bacteria and fungi
Boardworks KS3 Science 2008 Microbes and Disease Microbes have many uses that are based on the fact that they can be grown. Bacteria grow in milk to make it ‘go off’. This type of bacterial growth is used to make milk into yoghurt. Cheese is also produced using certain strains of bacteria. Fungi can also be used to make food. The meat substitute Quorn™ is a protein produced using fungi.

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Using yeast Boardworks KS3 Science 2008 Microbes and Disease Yeast is a type of fungus and carries out respiration. The respiration of this microbe can be used in different ways in baking bread and in brewing. The aerobic respiration of yeast is used to make bread rise. Yeast uses the sugar in bread dough to carry out aerobic respiration: oxygen carbon dioxide glucose + water ( energy) What gas produced by the aerobic respiration of yeast causes bread to rise?

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Using yeast Boardworks KS3 Science 2008 Microbes and Disease The anaerobic respiration of yeast is used to make beer and wine. In this case, the yeast respires without oxygen and produces alcohol (ethanol). This process is known as fermentation. Yeast converts the sugar into alcohol by anaerobic respiration: glucose carbon dioxide ethanol + ( energy)

17 How microbes cause disease
Boardworks KS3 Science 2008 Microbes and Disease How microbes cause disease

18 Microbes can cause disease
Boardworks KS3 Science 2008 Microbes and Disease The diseases caused by microbes, and their severity, depend on the type of microbe: bacteria food poisoning sore throats tuberculosis (TB) tetanus cholera typhoid bacterial meningitis influenza (flu) mumps chickenpox smallpox polio HIV / AIDS virus viral meningitis fungal sinusitis athlete’s foot fungi onychomycosis (causes discoloured toe nails) Microbes and Disease Worksheet 1, including an excel spreadsheet, accompanies this slide. The data given in the spreadsheet does not contain all countries – some have been excluded to make the data easier to handle. This activity is best carried out using excel. If the students use the data in excel the sort button can be used to find the maximum and minimum values for each continent. In order to calculate the average for each continent students should insert an equation, e.g. =sum(A1:A10)/10. The answers should be: Highest and lowest values Africa: 28–1,211 Asia: 6–713 Europe: 4–150 North America: 3–405 Oceania: 6–475 South America: 16–280 Africa has the largest range of data. Averages Africa: 495 Asia: 186 Europe: 40 North America: 67 Oceania: 125 South America: 115

19 How do microbes enter the body?
Boardworks KS3 Science 2008 Microbes and Disease Microbes can enter the body in many different places: eyes ears nose mouth genitals cuts skin How do the diseases caused by microbes spread?

20 How does disease spread?
Boardworks KS3 Science 2008 Microbes and Disease Microbes and disease worksheet 2 accompanies this slide.

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Fighting disease

22 Defences against disease
Boardworks KS3 Science 2008 Microbes and Disease Harmful microbes can cause disease by damaging body cells. Once microbes have entered the body, it’s important that they are removed as quickly as possible to reduce damage. Photo credit: Jupiterimages Corporation The body’s immune system uses specialized cells called white blood cells to identify and destroy the microbes. How does the body try to stop harmful microbes from entering?

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The body’s defences Boardworks KS3 Science 2008 Microbes and Disease

24 What do white blood cells do?
Boardworks KS3 Science 2008 Microbes and Disease If harmful microbes enter the body the immune system produces white blood cells to help defend it from microbes. bacteria antigen Some white blood cells can destroy microbes by engulfing them. white blood cell Some white blood cells are able to produce chemicals called antibodies. These pair with matching antigens on the surfaces of microbes and so help the white blood cells to engulf microbes.

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Destroying microbes Boardworks KS3 Science 2008 Microbes and Disease

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Producing antibodies Boardworks KS3 Science 2008 Microbes and Disease Teacher notes The antibodies either make the bacteria easier for the white blood cell to engulf, cause the bacteria to clump together or neutralize harmful toxins produced by the bacteria.

27 Preventing the spread of disease
Boardworks KS3 Science 2008 Microbes and Disease There are several methods that can help reduce the spread of disease: disinfecting surfaces disinfecting skin using antiseptics sterilizing equipment using food preservatives in food personal hygiene. Photo credit: Jupiterimages Corporation Teacher notes Pupils could be asked how each method can reduce the spread of disease. They could also be prompted to think about when and where it would be important to sterilize equipment. The spread of disease can also be reduced by vaccinating the population and using antibiotics.

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What are antibiotics? Boardworks KS3 Science 2008 Microbes and Disease Antibiotics are chemicals used to treat bacterial infections. These chemicals kill or stop the growth of bacteria. However, some types of bacteria are no longer affected by certain antibiotics – this is called antibiotic resistance. This can be a problem as without effective antibiotics some people might not be able to fight the infection themselves. Photo credit: Jupiterimages Corporation Teacher notes Pupils may have heard about MRSA (methicillin-resistant Staphylococcus aureus) in the media. It could be helpful to explain that MRSA is a type of antibiotic resistant bacteria which may affect people in with a low immune system, i.e. people in hospital.

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What are vaccines? Boardworks KS3 Science 2008 Microbes and Disease Vaccines can protect people from diseases, such as measles. Vaccines contain dead or weakened strains of the harmful microbe that causes the disease. This stimulates the immune system. If the person comes into contact with the microbe again the immune system can destroy it quickly and effectively. Photo credit: Jupiterimages Corporation Why is it important that everyone is vaccinated?

30 Why do we need to have vaccinations?
Boardworks KS3 Science 2008 Microbes and Disease

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Who invented vaccines? Boardworks KS3 Science 2008 Microbes and Disease

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Summary activities

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Glossary Boardworks KS3 Science 2008 Microbes and Disease antibiotics – A chemical prescribed as medicine to kill bacteria inside the body. antibody – A chemical produced by white blood cells to fight microbes that cause disease. bacteria – A type of microbe that is single-celled. fungi – A type of microbe that feeds off other living things. immunity – Resistance to infection caused by a microbe. microbe – A very small living thing. transmission – The spread of a disease from person to person. viruses – A type of microbes that can only grow and reproduce within other living things. vaccine – Dead or weakened strains of a microbe, designed to provide immunity to a disease.

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Anagrams Boardworks KS3 Science 2008 Microbes and Disease

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Multiple-choice quiz Boardworks KS3 Science 2008 Microbes and Disease


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