Species at war. Information sheets and question sheets. Science: Biology. Microorganisms, pathogens and the body s defences.

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1 Species at war Information sheets and question sheets Subject(s): Science: Biology Age group(s): Topic(s): Microorganisms, pathogens and the body s defences Source This resource was originally developed by Ann Horton and adapted by the EAL Nexus team. License information This resource is free to use for educational purposes. British Council 2015 This project and its actions were made possible due to co-financing by the European Fund for the Integration of Third-Country Nationals

2 Microorganisms: information sheet Microorganisms are very small living things. You need a microscope to see most of them. micro = very small organism = something alive Sometimes they are called microbes. Bacteria are very small. They are single-celled organisms. They have a cell wall. They do not have a nucleus. Some bacteria are useful. Some bacteria cause disease. Viruses are extremely small. They are much smaller than bacteria. They are not made of cells. They have a protein coat round their genetic material. Viruses cause disease. You can see some fungi without a microscope. Some fungi are single-celled organisms. Some are made of long threads. Some fungi are useful. Some fungi cause disease. bacteria viruses microscope fungi

3 Microorganisms: question sheet List the three types of microorganism. Smallest Biggest Tick true or false. True False Correct the false sentences. Viruses are made of cells. All bacteria cause disease. Bacteria are singlecelled organisms. Viruses are larger than bacteria. Some fungi are useful. Choose a word. cells viruses protein single-celled fungi genetic bacteria microorganisms Write the correct word in the space. are very small living things., and fungi are examples of these. Bacteria are. Viruses are not made of. They have a coat round their material. Some bacteria and are useful.

4 Pathogens: information sheet Microorganisms that cause disease are called pathogens (microbes). Microorganisms cause diseases in different ways: Influenza (flu) is caused by a virus. Salmonella (food poisoning) is caused by bacteria. Athlete s foot is caused by a fungus. Microorganisms need three things to help them reproduce: warmth Diseases are caused by: moisture nutrients (food for growth) Viruses attack and invade our body cells and damage them. virus cell Bacteria produce toxins (poisonous chemicals) which make us ill. Fungal infections are spread through direct contact (by sharing towels). Microorganisms can enter our body in many different places: nose ears mouth eyes genitals cut skin

5 Pathogens: question sheet List the three types of pathogens Choose a word. damage invade virus toxins microorganisms diseases Write the correct word in the space. Pathogens are that cause disease. Different pathogens cause different. For example, influenza is caused by a. Bacteria produce which make us ill. Viruses attack and our body cells and them. Microorganisms can enter our body in different places. Find the 7 places in the wordsearch. The first one has been done for you. Find the words here. Write the words here. B C F G T U S eyes S E Y E P Y F N K O N L E M T S K I N S G C R H T U O M S U V A W N H A E T L I L O S G E S R A E P W Z F N P Q

6 Transmission of microorganisms: information sheet Some diseases are infectious. That means you can catch them from someone else. Pathogens are transmitted (passed on) from one person to another in a number of ways. By breathing droplets By eating or drinking contaminated food or liquid By touch (physical contact) By insects or animals By blood From mother to child Salmonella is a bacteria. It is passed on by eating contaminated food. Influenza (flu) is a virus. It is passed on by droplets in the air from an infected person, or by physical contact. Athlete s foot is a fungus. It is passed on by physical contact. It is very important to wash your hands after you use the toilet and before you eat.

7 Transmission of microorganisms: question sheet Write the following sentence out correctly: you can catch/is a disease that/from someone else./an infectious disease The pictures below show the ways in which diseases can be transmitted (passed from one person to another). Match each picture to its correct description. by insects or animals by blood from mother to child by touch (physical contact) by breathing droplets by eating or drinking contaminated food or liquid

If you cut yourself, platelets in the blood stick together to form a clot. They seal the cut with a scab to stop microbes getting in.

8 The body s defences, 1: information sheet The human body has a number of barriers which form the first line of defence against pathogens. They help to prevent many pathogens from entering the body. The skin prevents microbes from getting into the blood. If you cut yourself, platelets in the blood stick together to form a clot. They seal the cut with a scab to stop microbes getting in. skin scab Tears and sweat contain chemicals which destroy bacteria. barrier tears sweat Stomach acid destroys bacteria in food. Sticky mucus in your nose and airways helps to trap microorganisms. Tiny hairs called cilia then move the mucus on. stomach mucus cilia (tiny hairs in the nose)

9 The body s defences, 1: question sheet Complete the names of the 5 barriers which the body uses to prevent microbes from entering the body. 1. s a _ 4. m 2. t 5. s 3. s _ Match the barrier to the part(s) of the body where it is found. tear all over the body acid nose and airways skin stomach mucus eyes Write out 4 correct sentences about the body s barriers. Use a word or phrase from each column. Mucus Skin Stomach acid A scab seals destroys traps prevents bacteria in food. a cut. microbes from entering the body. microorganisms.

10 The body s defences, 2: information sheet If pathogens get past the first line of defence and enter your body, there is a second line of defence: the immune system. The white blood cells are a vital part of the immune system. They fight infections in our bodies. Phagocytes are one type of white blood cell. They destroy pathogens by engulfing them. Yellow phagocyte engulfs the pathogen B-cells and T-cells are another type of white blood cell (lymphocytes). Each pathogen leaves an antigen on the surface of cells it infects. T- cells recognise the pathogens by receptors on their surface. B-cells produce antibodies. They are Y-shaped. These antibodies lock on to the antigens. The antigens can then be destroyed in different ways. Each antibody is specific to one antigen. This means that each antibody can only lock on to just one type of antigen. Different B-cells with antigen receptors After the immune system has produced antibodies for one illness, some of the antibodies remain as memory cells. This means that your body will react more quickly to fight off that illness if you meet it again.

11 The body s defences, 2: question sheet The sentences below all contain a mistake. Write each sentence out with the CORRECT facts. 1. Phagocytes are a type of pathogen. 2. T-cells produce antibodies. 3. Antibodies are many different shapes. 4. Antibodies can lock on to any antigen. The sentences below describe what happens when pathogens attack a person s body and the immune system fights them. They are in the wrong order. The antibodies help to destroy the pathogens. T-cells recognise the pathogens. Pathogens enter the body. The person begins to feel well again. B-cells make antibodies. The pathogens reproduce and make toxins. Write them out in the CORRECT order here

12 Antibiotics and vaccines: information sheet Antibiotics are medicines that are prescribed by doctors. They do not affect viruses, so are not prescribed for colds or flu. Antibiotics kill bacteria Antibiotics stop bacteria from growing. Some types of bacteria are no longer affected by certain antibiotics. This is called antibiotic resistance. This can be a problem, as some people might not be able to fight infections themselves, without the help of effective antibiotics. There are lots of Antibiotics kill the illness The antibiotic germs. A few are as well as the good bacteria resistant bacteria antibiotic resistant. protecting the body. grow. Vaccines are another way of helping your immune system to fight some diseases. The process is called vaccination or immunisation. Dead or inactive microbes are injected into your body. You do not become ill, because the microbes are not active, but your immune system produces antibodies to fight the microbes. This means that if this disease ever infects your body, you already have the antibodies there to fight it off.

13 Antibiotics and vaccines: question sheet Read the paragraph below. Cross out the wrong word in each pair of bold and italic words. The first one has been done for you. Antibiotics and fungi / vaccines can help your immune / digestive system to fight diseases. Antibiotics are medicines / pathogens which can kill viruses / bacteria but not viruses / bacteria. Unfortunately, some bacteria have become natural / resistant to certain antibiotics, so they can no longer be killed by them. Vaccines contain dead or inactive / live microbes which make your immune system react to them and produce antigens / antibodies. If the real, active disease tries to infect you after that, the pathogens / antibodies will fight it off. Across 2. Bacteria which are not affected by a particular antibiotic. 6. These can be killed by antibiotics. 7. A microorganism which is not affected by antibiotics. Down 1. A form of a pathogen which will not give you the disease it causes. 3. Drugs which kill or weaken bacteria. 4. White blood cells make these to destroy microorganisms. 5. Contain inactive or dead microbes.

Name Date Class. This section explains what kinds of organisms cause infectious disease and how infectious diseases are spread.

Name Date Class. This section explains what kinds of organisms cause infectious disease and how infectious diseases are spread. Fighting Disease Name Date Class Infectious Disease This section explains what kinds of organisms cause infectious disease and how infectious diseases are spread. Use Target Reading Skills Before you read,