Summary Sheets. Viruses are usually not considered to be living because they do not carry out any of the seven life processes for themselves.

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1 Summary Sheets Microbes Microbes, or micro-organisms, can only be seen using a microscope. There are three main types of microbes: viruses, bacteria and fungi. The most common fungus microbes are yeasts. Viruses are smaller than bacteria which are smaller than yeast Viruses are usually not considered to be living because they do not carry out any of the seven life processes for themselves. Bacteria and yeasts are important in making some foods and drinks. Yeasts are used to make bread dough rise. The cells use oxygen, from the air found in pockets in the dough, for aerobic respiration. This process produces carbon dioxide, which makes the bread rise. glucose + oxygen carbon dioxide + water Yeast cells are also used to make beer and wine. In this case there is no air and so the yeast cells use anaerobic respiration. When yeasts cells use anaerobic respiration it is called fermentation. The ethanol is a waste product of this reaction. glucose carbon dioxide + ethanol (a sugar) The number of an organism in an area is called a population. In good conditions (warm, moist, plenty of sugar) a population of yeast cells will grow rapidly. The population stops growing if something runs out (e.g. sugar). The thing that stops the population growing is called a limiting factor. the effect of a limiting factor Number of yeast cells Time Page 1 of 2 Exploring Science edition

2 Summary Sheets (continued) Diseases Some microbes cause infectious diseases (diseases that can be spread from person to person). The microbes are said to infect you. The effects the microbes have on your body are known as symptoms. A doctor observes symptoms to come up with a diagnosis. Microbes can be spread by the air, water, touch, food, animals and sex. Disease Microbe that causes it Symptoms How it is spread colds and flu virus sore throat, running nose, fever air food poisoning bacteria vomiting, diarrhoea food cholera bacteria vomiting, diarrhoea water athlete s foot fungus sore cracked skin between the toes touch Some ways that diseases can be stopped from spreading are: making sure sewage is treated and disposed of properly adding chlorine to water to kill bacteria drying, freezing or refrigerating foods pasteurising milk using disinfectants, antiseptics and soaps immunising people with vaccines. Your body has natural defences to stop microbes getting in (e.g. skin, mucus in the trachea and nose, ciliated epithelial cells to sweep mucus away). Your body also has ways of destroying microbes. These include: a chemical in tears that kills some bacteria acid in the stomach that kills some bacteria white blood cells that engulf microbes other white blood cells that make antibodies to help destroy microbes. Babies do not have fully developed immune systems. Antibodies can pass through the placenta and are found in breast milk. These help the baby to fight infections. For many diseases, once you have had the disease (or been immunised) you will not get it again (e.g. chickenpox). This is because the antibodies against these microbes stay in the blood. Some diseases can be cured using antibiotics. These are medicines that kill off bacteria. Some bacteria, however, are unaffected by antibiotics they are resistant to them. Using too many antibiotics only leaves behind the resistant bacteria, which then cause diseases that are difficult to treat. Page 2 of 2 Exploring Science edition 9

3 Level Ladder Name lass Date My Target Level is: My final level is: Tick the boxes that apply. Or use traffic lights to show how confident you are (red = I don t know this ; orange = I m not very confident about this ; green = I m confident I know this ). Level At the end of the Unit: I can do this This needs more work Working towards Level 4 Appreciate that people are used to trial new medicines. Level 4 Describe a range of jobs that people do to look after patients in a hospital. Point out some hazards when working with microbes. Recall some ways in which microbes can be spread. Recall the names of the seven life processes. Level 5 Recall that theories about disease have changed. Describe an old model of disease and explain how it does not match current evidence. Describe how our knowledge about the spreading of diseases has increased with increasing knowledge about microbes. Describe how new scientific knowledge (e.g. about the causes of disease, hygiene) alters people s behaviour. Spot some trends and patterns in data from investigations. Use charts and graphs to identify trends. Explain how risks are controlled in practical work involving microbes. Recall that immunisation is a way of protecting us from infectious diseases. Recall that bacteria, some fungi and viruses are classified as micro-organisms. Describe how microbes are used in the production of some foods and drinks. Recall the names of some of the diseases caused by certain microbes and describe how those diseases are spread. Page 1 of 2 Exploring Science edition 6

4 Level Ladder (continued) Name lass Date Level At the end of the Unit: I can do this This needs more work Level 6 Recognise how a theory is used to make predictions that are then tested. Recall some of the evidence that has led to current ideas about disease. Spot trends and patterns in data from first-hand and secondary sources and draw conclusions from them. Draw conclusions from first-hand and secondary sources and link them to scientific facts. Identify reasons why correct theories might not be accepted. Describe the body s main methods of defence against disease-causing microbes. Recall that antibiotics are only effective against bacteria and not viruses. Level 7 Recognise that some theories are driven by commercial need. Explain how trends are more easily spotted using tables, charts and graphs. Explain how immunisation improves the body s own immune response. Recall that antibiotics may be effective against a wide range of bacteria or only a specific species. Level Explain how scientists have used evidence to put together new theories about disease transmission and develop new drugs. Identify and explain the typical phases in a population growth curve. Describe what protoctists are and how they are classified. Page 2 of 2 Exploring Science edition 7

5 Word Sheets a Superbugs/A hidden world bacterium data fungus microbe micro-organism organism virus yeast A type of microbe bigger than viruses. Plural = bacteria. The observations from an experiment. A type of organism that is different from animals, plants and bacteria. Examples include mushrooms and yeasts. Plural = fungi. A very small living thing. Another name for a microorganism. A very small living thing. Another name for a microbe. A living thing. The smallest type of microbe. Most scientists do not think that viruses are living because they do not carry out the seven life processes for themselves. A type of fungus with only one cell. It is therefore a microbe. Yeasts are bigger than bacteria. a Focus on: Microbe structure chromosome crow-mow-sowm A long piece of material on which genes are found. classified Placing things in their groups according to their characteristics. flagellum flaj-jell-um A tail that some microbes use to move about. Plural = flagellae. gene jean Genes contain instructions for making things that a cell needs. protein coat The outside of a virus that is made of proteins. replication When a virus reproduces inside a living cell. strand of genes Genes contain instructions for making things that a cell needs. Viruses only have a small number of genes, arranged on a strand. Animals have many thousands of genes carried on chromosomes. b Microbes in action aerobic respiration air-ro-bick Process that releases energy from glucose. Needs oxygen from the air. arbon dioxide and water are produced as wastes. anaerobic respiration an-air-ro-bick A type of respiration that does not need oxygen. budding The way yeast cells divide. A new small cell (a bud) starts to grow out from another cell. Page 1 of 3 Exploring Science edition 77

6 Word Sheets (continued) b Microbes in action (continued) ethanol fermentation limiting factor population starter culture Often just called alcohol. Produced when yeasts ferment sugar. The type of anaerobic respiration carried out by yeast. It produces carbon dioxide and ethanol. Something that stops a population growing. The numbers of a certain organism found in a certain area. Small amount of actively growing microbe that is added to a mixture to grow large amounts of microbes. c Under attack/holera: the evidence diagnosis die-agg-no-sis What a doctor thinks is causing a person s symptoms. disease When some processes that happen in your body do not work in the way they should. fever fee-ver A high body temperature. infect When a microbe gets into your body you are infected by it. infectious in-feck-shus A disease that can be spread from person to person or from animal to person is infectious. learning A type of behaviour that changes based on the experiences of the animal. symptoms The effects that a disease has on your body. theory theer-ree A scientific idea that can be tested. d Stopping the spread/self-defence antibody Small chemical made by some white blood cells. Antibodies attach to microbes and help to destroy them. antiseptic Weak disinfectant safe to use on human skin. ciliated epithelial cell sil-lee-ay-ted ep-pee-theel-ee-al sell ells in the trachea that have microscopic hairs (cilia) growing from them that wave to move mucus up to the gullet to be swallowed. clot When blood becomes solid. Makes a scab when it is on the surface of the skin. disinfectant Strong chemical used to kill microbes. engulf When a white blood cell completely surrounds a microbe and digests it, it is said to engulf the microbe. Page 2 of 3 Exploring Science edition 7

7 Word Sheets (continued) d Stopping the spread/self-defence (continued) mucus mew-cus Sticky substance used to trap microbes and dust. Found in nose and trachea. natural defences Your body s way of trying to keep microbes out (e.g. skin) or killing them if they get inside you (e.g. stomach acid). pasteurisation pas-ter-eyes-ay-shun Process in which milk is heated up to 70 for about 15 seconds, which is enough to kill the most harmful bacteria in it. scab A dry blood clot on the surface of the skin. trachea track-ee-a Another name for the windpipe. white blood cell A type of blood cell that helps to destroy microbes. They either engulf microbes or make antibodies. d Focus on: HIV and AIDS AIDS Disease caused by HIV. Stands for: Acquired Immune Deficiency Syndrome. HIV Human Immunodeficiency Virus. It causes AIDS. HIV positive Someone who is infected with HIV. replicate Viruses cannot reproduced on their own. They use the new cell that they have infected to help them make new copies of the virus. We say that the virus particles replicate. T4 lymphocyte A type of white blood cell needed to destroy microbes. e Beating infections/medicine men/medical problems antibiotic ant-ee-by-ot-tick Medicine that can kill bacteria but not viruses. immune imm-you n If you cannot get a disease you are said to be immune to it. immunisation imm-you n-eyes-ayshun Making people or animals immune to diseases. infect When a microbe gets into your body you are infected by it. medicine A drug that helps the body to ease the symptoms of a disease or cure the disease. resistant Bacteria that are not affected by an antibiotic are said to be resistant to it. vaccine vack-seen A mixture containing microbes that normally cause disease, but which have been treated so that they don t. Often injected into people to make them immune. variation The differences between things. Page 3 of 3 Exploring Science edition 79