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KnowIT! Infection and Response Part 1 Communicable diseases Viral diseases Bacterial diseases Fungal diseases Protist diseases  Infection and Response part 1 – Infectious diseases Pathogens are micro organisms that cause infectious disease. Pathogens may infect plants or animals and can be spread by direct contact, by water or by air. Pathogens depend on the host to provide the suitable conditions and nutrients that they need to grow and reproduce. Pathogens can be bacteria, viruses, fungi or protists. Viral diseases Bacterial diseases Viruses may reproduce rapidly Bacteria may reproduce rapidly Viruses live and reproduce inside Bacteria may produce toxins cells causing damage that damage tissues and make us feel ill  Infection and Response part 1 – Infectious diseases Pathogens may infect plants or animals and can be spread by direct contact (D), by water (W) or by air (A). A W D W D D A  Infection and Response part 1 – Viral diseases Examples of Viral Diseases Measles Symptoms of fever and a red skin rash Can be fatal if complications occur Spread by inhaling droplets containing the virus from sneezes and coughs It is controlled by vaccinating young children HIV Initially causes a flu-like illness and spread by sexual contact or exchange of body fluids such as blood when drug users share needles Unless HIV is successfully controlled with antiretroviral drugs, the virus will attack the body’s immune cells Late stage HIV or AIDS occurs when the body’s immune system can no longer deal with other infections or cancers Tobacco Mosaic virus Common plant virus which enters through a damaged epidermis Seen as a distinct mosaic discolouration pattern on the leaves Affects growth as photosynthesis cannot occur as efficiently Control by removing affected leaves and destroying pests which caused initial epidermal damage  Infection and Response part 1 – Bacterial diseases Examples of Bacterial Diseases Salmonella Salmonella food poisoning is spread by bacteria ingested in food or on food prepared in unhygienic conditions. Bacteria secrete toxins and cause symptoms including fever, abdominal cramps, diarrhoea and vomiting. In the UK, poultry are vaccinated against salmonella to control the spread of the disease. Gonorrhoea Sexually transmitted disease (STD) caused by bacteria. Causes a thick yellow or green discharge from the penis or vagina and pain when urinating. Can be controlled with antibiotics or barrier methods of contraception such as a condom. Easily treated with the antibiotic penicillin until many resistant bacterial strains were found.  Infection and Response part 1 – Fungal and Protist diseases Example of a Fungal Disease Example of a Protist Disease Rose Black Spot Malaria ▪ The malaria causing protist is spread by mosquitoes feeding on infected blood and then biting a human ▪ Mosquitoes are vectors as they pass on malaria but do not suffer themselves ▪ Symptoms include recurrent fever and malaria can be fatal ▪ Purple or black spots develop on leaves ▪ Control the spread by preventing ▪ Leaves often turn yellow and drop off mosquitoes breeding and use mosquito ▪ Photosynthesis is reduced. Growth is nets to avoid being bitten affected as a result ▪ Fungal spores spread by wind or water ▪ Treat by removing infected leaves and burning them ▪ Spray with fungicide (a pesticide which is used to kill fungus)  Infection and Response part 1 – Types of diseases Method of Disease Symptom Control spread of disease by: Caused by: transmission Preventing breeding of Recurrent fever By a vector from an Malaria infected person mosquitoes or use of a net to Protist prevent being bitten Enters via wounds Remove infected leaves and Tobacco Mosaic pattern in epidermis control pests which are Virus Mosaic Virus on leaves caused by pests damaging leaves Droplet infection Fever Measles Red skin rash from sneezes and Child Vaccination Virus coughs Green discharge Direct sexual Use of a condom and treat Gonorrhoea from penis or contact or body infected person with Bacteria vagina fluids antibiotics Rose Black Purple black Spores carried via Remove infected leaves and Fungus Spot spots on leaves wind or water spray with pesticide Food prepared in Fever, cramp, Improve food hygiene, wash unhygienic Salmonella vomiting, conditions or not hands, vaccinate poultry, cook Bacteria diarrhoea food thoroughly cooked properly QuestionIT! Communicable diseases Part 1a Viral diseases Bacterial diseases Fungal diseases Protist diseases  Infection and Response part 1 – QuestionIT 1. What is the definition of a pathogen? 2. List four types of micro-organism which can act as pathogens. 3. Copy and complete the table to describe one similarity and one difference between how bacteria and viruses act as pathogens. Pathogen Similarity Difference Bacteria Virus 4. What do pathogens need from the host organism? 5. Complete the sentences: HIV can be successfully controlled with ______drugs. If the immune system is badly damaged then _____ may develop.  Infection and Response part 1 – QuestionIT 6. Copy and complete the table for each disease. Disease Symptom Method of Control spread of disease Caused by: transmission by: Measles Fever Child Vaccination Red skin rash Fever, cramp, Food prepared in Bacteria vomiting, unhygienic diarrhoea conditions or not cooked properly Rose Black Purple black Remove infected leaves and Spot spots on leaves spray with pesticide Gonorrhoea Direct sexual Use of a condom and treat Bacteria contact or body fluid infected person with antibiotics exchange Recurrent fever By a vector from an Preventing breeding of infected person mosquitoes or use of a net to prevent being bitten Tobacco Mosaic Mosaic pattern Virus Virus on leaves  Infection and Response part 1 – QuestionIT 7. Look at this photograph. Suggest how pathogens could be transferred in this situation. What could people do to reduce the spread of pathogens? AnswerIT! Communicable diseases Part 1 Viral diseases Bacterial diseases Fungal diseases Protist diseases  Infection and Response part 1 – AnswerIT 1. What is the definition of a pathogen? Micro-organisms which cause infectious disease in animals & plants. 2. List four types of micro-organism which can act as pathogens. Bacteria, Virus, Protist, Fungus. 3. Copy and complete the table to describe one similarity and one difference between how bacteria and viruses act as pathogens. Pathogen Similarity Difference Bacteria Reproduce rapidly Produce toxins that inside the body damage tissues Virus Reproduce rapidly Live and reproduce inside the body inside cells causing cell damage  Infection and Response – AnswerIT 4. What do pathogens need from the host organism? Suitable conditions and nutrition to be able to grow and reproduce. 5. Complete the sentences: HIV can be successfully controlled with antiretroviral drugs. If the immune system is badly damaged then AIDS may develop.  Infection and Response part 1 – AnswerIT 6. Copy and complete the table for each disease. Disease Symptom Method of Control spread by: Caused by: transmission Measles Fever Droplet infection Child Vaccination Virus Red skin rash from sneezes and coughs Salmonella Fever, cramp, Food prepared in Improve food hygiene, wash Bacteria vomiting, diarrhoea unhygienic conditions or not hands, vaccinate poultry, cooked properly cook food thoroughly Rose Black Purple black spots Spores carried via Remove infected leaves and spray Fungus Spot on leaves with pesticide wind/water Gonorrhoea Green discharge Direct sexual contact Use of a condom and treat Bacteria or body fluids infected person with antibiotics from penis or vagina Malaria Recurrent fever By a vector from an Preventing breeding of mosquitoes Protist infected person or use of a net to prevent being bitten Tobacco Mosaic pattern on wounds in Remove infected leaves and Virus Mosaic Virus leaves epidermis caused control pests which are by pests damaging leaves  Infection and Response part 1 – AnswerIT 7. Look at this photograph. Suggest how pathogens could be transferred in this situation. What could people do to reduce the spread of pathogens? Could reduce the Direct contact by spread by: touching a Hand over mouth if contaminated coughing and then surface. washing. Droplet infection if Use a tissue if sneezing someone sneezes or and then dispose of it coughs in the lift. and wash hands. Air - if fungal spores Washing hands with are present. soap after visiting the toilet. Wear a face mask. LearnIT! KnowIT! Infection and Response Part 1b Human defence systems Vaccination Antibiotics and painkillers Discovery and development of drugs  Infection and Response part 1 – Human Defence Systems n o trachea s bronchus e Nasal hairs, sticky The human body Respiratory system is mucus and cilia prevent pathogens has several non lined with mucus to trap specific ways of dust and pathogens. Cilia entering through move the mucus the nostrils. defending itself ski upwards to be from pathogens n swallowed. getting in. stomach video Hard to penetrate Stomach acid (pH1) waterproof barrier. Glands kills most ingested secrete oil which kill pathogens microbes.  Infection and Response part 1 – Human Defence Systems Sometimes pathogens gain entry to the body. The immune system takes over to destroy them. The white blood cells are part of the immune system. Pathogens are identified by white blood cells because they have different surface proteins. We call these surface proteins antigens. White blood cells act in 3 ways to defend the body: 1. White blood cells (called phagocytes) engulf the pathogens and digest them. This is called phagocytosis. Video phagocytes 2. White blood cells (called lymphocytes) identify the antigen on the pathogen. They make specific antibodies to destroy the pathogens. This can take time and so an infection may occur. If a person is infected again by the same pathogen, the white blood cells make the antibodies much faster. Video lymphocytes 3. Bacteria may produce toxin (poison). White blood cells release specific antitoxins to neutralise the effect of the toxin.  Infection and Response part 1 – Vaccination Communicable diseases can be dangerous leading to epidemics or pandemics. Vaccination can be used to enhance the immune system to reduce the chances of this happening. A vaccine contains a small amount of dead or inactive form of the pathogen that can be introduced into the body. Lymphocyte pathogen White blood cells Antibodies are released Pathogens are destroyed by detect pathogens in into the blood. antibodies. the vaccine.  Infection and Response part 1 – Vaccination If the body becomes re-infected with the same pathogen then the white blood cells are prepared. The white blood cells can respond much more quickly and make more of the right type of antibodies much more quickly. White blood cells Antibodies are made Pathogens are destroyed detect pathogens. and released into the by the antibodies much blood much faster and faster. in larger amounts. This means that the person is unlikely to suffer the symptoms of the harmful disease. Infection has been prevented by enhancing the immune system.  Infection and Response part 1 – Antibiotics An antibiotic is a drug that helps to cure a bacterial disease by killing the infective bacteria inside the body. Different bacterial Antibiotics infections need a cannot be used different to treat viral antibiotic. pathogens. Penicillin is a well It is difficult to develop known antibiotic Using antibiotics drugs to kill viruses medicine. has greatly reduced without harming body deaths. tissues because viruses live and reproduce inside cells.  Infection and Response part 1 – Antibiotics Bacteria can mutate. Sometimes this makes them resistant to antibiotic drugs. The mutated bacteria are not killed. Increasing numbers of different bacteria are becoming resistant and this is of concern. A Red = bacteria colonies Bacteria are A resistant to Disc soaked antibiotic A in antibiotic Clear = no B Bacteria are bacterial killed by colonies antibiotic B  Infection and Response part 1 –– Painkillers A doctor will not prescribe antibiotics for a viral infection as they do not work. Antibiotics can only be used for bacterial infections Painkillers, steroids or anti inflammatory medicines can be used to relieve the symptoms of viral infections. Symptoms may include: fever, muscle ache, headache or a runny nose. Painkillers do not kill pathogens. QuestionIT! Infection and Response Part 1b Human defence systems Vaccination Antibiotics and painkillers  Infection and Response – QuestionIT 1. Name and describe 3 ways the human body defends against the entry of pathogens. 2. Draw a series of pictures to show how white blood cells carry out phagocytosis. 3. What is an antigen? 4. Why will the antibody produced for measles not be effective in other diseases? 5. Why are dead or inactive pathogens used in a vaccine? 6. What happens if the live pathogen invades the body after being vaccinated? 7. What is an antibiotic and what is it used for?  Infection and Response – QuestionIT 8. Why is there a growing concern about bacterial resistance to antibiotics? 9. Which one of these statements is true? Painkillers are used to treat the symptoms of a disease and kill the pathogens which cause it. Painkillers are used to kill the pathogens causing a disease. Painkillers are used to treat the symptoms of a disease but do not kill the pathogens. AnswerIT! Infection and Response Part 1b Human defence systems Vaccination Antibiotics and painkillers  Infection and Response – AnswerIT 1. Name and describe 3 ways the human body defends against the entry of pathogens. Skin – barrier, nose - nasal hairs , mucus and cilia, trachea & bronchi – mucus to catch, cilia to remove from lungs, stomach - HCl acid kills. 2. Draw a series of pictures to show how white blood cells carry out phagocytosis. Diagram of white blood cell moving towards and engulfing foreign body and then adding digestive enzymes. 3. What is an antigen? A protein on the surface of a pathogen. 4. Why will the antibody produced for measles not be effective in other diseases? Antibody has a specific shape which fits with a specific antigen.  Infection and Response – AnswerIT 5. Why are dead or inactive pathogens used in a vaccine? To stimulate white blood cells to make antibodies without causing the disease. 6. What happens if the live pathogen invades the body after being vaccinated? White blood cells able to respond much faster and produce more antibodies quicker to destroy the pathogens so the person doesn’t suffer the symptoms of the disease. 7. What is an antibiotic and what is it used for? Kills bacteria inside the body without harming human cells.  Infection and Response – AnswerIT 8. Why is there a growing concern about bacterial resistance to antibiotics? The resistant bacteria are not killed and can continue to multiply inside the body making the person very ill and infecting others too. 9. Which one of these statements is true? Painkillers are used to treat the symptoms of a disease and kill the pathogens which cause it Painkillers are used to kill the pathogens causing a disease Painkillers are used to treat the symptoms of a disease but do not kill the pathogens. LearnIT! KnowIT! Infection and Response Part 2 Discovery of Drugs Development of Drugs Monoclonal Antibodies (Biology HT only)  Infection and Response part 2 – Discovery & drug development Traditionally drugs Aspirin is a painkiller were extracted from and plants and anti-inflammatory micro-organisms. drug. This was first video found in willow bark. Foxglove plants have been a source of the drug digitalis which acts on the heart. Fleming noticed the Alexander Fleming fungus on unwashed is famous for equipment and went discovering on to discover its Penicillium mould. antibiotic properties.  Infection and Response part 2 – Development of drugs Most new drugs are developed and synthesised (made) in a laboratory by chemists in the pharmaceutical industry. The initial chemical may have been sourced from a plant. New drugs must be tested Preclinical tests must be and trialled to check: carried out before humans ✔ Efficacy - that the drugs are allowed to take the drug. work ✔ Toxicity - that the drug is These preclinical tests are not poisonous done on cells, tissue samples ✔ Dose - the most suitable and live animals. amount to take  Infection and Response part 2 – Drug development If successful the new drug will proceed to a clinical trial. The stages of a clinical trial are: Healthy volunteers try small doses of the drug to check it is safe Stage 1 and has no side effects A small number of patients try the drug at a low dose to see if it Stage 2 works A larger number of patients take the new drug and different doses Stage 3 are trialled to find the optimum dose A double blind trial will occur to see how effective the new drug Stage 4 is. The patients are divided into groups video  Infection and Response part 2 – Drug development A double blind trial is carried out on patients who have the disease to make sure that it is actually the drug which is having an effect on the patients and not anything else. The details of everyone taking part in the trial is entered into a computer database. The computer groups people randomly. Each person receives a unique code and they receive the medicine which is labelled with the matching code. No-one knows who is receiving the real drug or a placebo until the end of the trial. The placebo is often the drug the patient was originally taking so they still receive medical treatment.  Infection and Response part 2 – Monoclonal antibodies (Biology HT) Monoclonal antibodies are identical copies of Mono = one one type of antibody produced in a laboratory. How to produce monoclonal antibodies: 1. A mouse is injected with a pathogen 2. White blood cells called lymphocytes produce antibodies 3. Lymphocytes are removed from the mouse and fused with rapidly dividing mouse tumour cells 4. The new cells are called hybridomas. 5. The hybridomas divide rapidly and release lots of antibodies which are then collected.  Infection and Response part 2 – Monoclonal antibodies (Biology HT) Monoclonal antibodies are specific to one binding site on the antigen. This means that we can use monoclonal antibodies to target a specific chemical or specific cells in the body. During pregnancy, a hormone called HCG is released into the blood. Monoclonal antibodies can detect the presence of this chemical at low levels and are used in pregnancy testing kits.  Infection and Response part 2 – Monoclonal antibodies (Biology HT) Monoclonal antibodies are also used in treating some cancers. The monoclonal antibodies are specific to the antigen on the cancer cells. A chemical which stops cells dividing can be bound to the monoclonal antibodies. The patient is given the monoclonal antibodies and they attach to receptors on the cancer cells. The chemical stops the cancer cells growing and dividing.  Infection and Response part 2 – Monoclonal antibodies (Biology HT) Monoclonal antibody research has raised some concerns about their ethical use. Mice are injected with Mice provide antibody pathogens and so they producing cells and will experience the tumour cells. Mice are disease symptoms. induced with cancer to get the tumour cells. Monoclonal antibodies have been Herceptin is used for breast successful in treating some cancers cancer. It is not toxic and is and diabetes. But there have been specific to breast cancer cells deaths when used to treat patients so few side effects. But it is with multiple sclerosis (MS). costly. QuestionIT! Infection and Response Part 2 Discovery of Drugs Development of Drugs Monoclonal Antibodies (Biology HT only)  Infection and Response – QuestionIT 1. Choose the answer from the box to complete the sentences. Willow tree bark Foxgloves Laboratory Mould Digitalis is a drug used for heart conditions. It originates from ______________. Aspirin is a drug used as a painkiller. It originates from ______________. Penicillin is an antibiotic drug. It originates from ______________.  Infection and Response – QuestionIT 2. Any potential new drug has to go through a series of tests. What is meant by the following terms? a) Efficacy b) Toxicity c) Optimum dose 3. Number these statements to show how drugs are tested. Drugs are trialled on live animals Drugs are trialled on people with the disease the drug is for Drugs are trialled in laboratories on cells and tissue cultures Drugs are trialled on healthy volunteers 4. Drugs companies often use a placebo in their trials. a. What is a placebo? b. Why is it used?  Infection and Response – QuestionIT Questions for Biology HT only 5. Place the statements in the correct order to show how monoclonal antibodies are produced. ❑ Mouse lymphocytes produce antibodies. ❑ The antibodies are collected and purified. ❑ Mouse lymphocytes are collected. ❑ Mouse is injected with a pathogen. ❑ Hybridoma cells are separated and cultured to form a clone. ❑ Mouse lymphocyte and mouse tumour cell are fused. ❑ The clone produces large quantities of antibody.  Infection and Response – QuestionIT 6. What are the applications of monoclonal antibodies? 7. Why do some people feel the use of monoclonal antibodies is unethical? AnswerIT! Infection and Response Part 2 Discovery of Drugs Development of Drugs Monoclonal Antibodies ( Biology HT only)  Infection and Response – AnswerIT 1. Choose the answer from the box to complete the sentences. Willow tree bark Foxgloves Laboratory Mould Digitalis is a drug used for heart conditions. It originates from Foxgloves. Aspirin is a drug used as a painkiller. It originates from willow tree bark. Penicillin is an antibiotic drug. It originates from mould.  Infection and Response – AnswerIT 2. Any potential new drug has to go through a series of tests. What is meant by the following terms? a) Efficacy how effective the drug is b) Toxicity how poisonous the drug is c) Optimum dose minimum amount of the drug which provides the best response 3. Number these statements to show the process of drug testing. 2. Drugs are trialled on live animals 4. Drugs are trialled on people with the disease the drug is for 1. Drugs are trialled in laboratories on cells and tissue cultures 3. Drugs are trialled on healthy volunteers  Infection and Response – AnswerIT 4. Drug companies often use a placebo in their trials. a. What is a placebo? A medicine that does not contain the drug that is being trialled. b. Why is it used? A placebo is used to check that there are no other factors which may cause the patient‘s condition to improve without the drug.  Infection and Response – AnswerIT Questions for Biology HT only 5. Place the statements in the correct order to show how monoclonal antibodies are produced. 2. Mouse lymphocytes produce antibodies. 7. The antibodies are collected and purified. 3. Mouse lymphocytes are collected. 1. Mouse is injected with a pathogen. 5. Hybridoma cells are separated and cultured to form a clone. 4. Mouse lymphocyte and mouse tumour cell are fused. 6. The clone produces large quantities of antibody.  Infection and Response – AnswerIT 6. What are the applications of monoclonal antibodies? Pregnancy testing Used to measure levels of hormones and other chemicals in blood Treat some cancers by delivering a toxic drug to the cancer cells To find various molecules in cells or tissues by binding to them with a fluorescent dye 7. Why do some people feel the use of monoclonal antibodies is unethical? Mouse has to suffer the disease deliberately Mouse is induced to have cancer Treatment not always safe It’s very expensive and money could be better used LearnIT! KnowIT! Infection and Response Part 3 Plant Disease (biology only)  Infection and Response part 3 – Plant disease (Biology HT) Plants suffer from a range of infections caused by pathogens or insect pests. We can detect a plant is diseased by these signs: Unusual growths Spots or discoloured Malformed leaves leaves or stems  Infection and Response part 3 – Plant disease (Biology HT) If a plant disease is suspected then it may be identified using: The presence of pests ✔Gardening manuals ✔Gardening websites ✔ Test kits containing Stunted growth monoclonal antibodies Areas of decay ✔Taking infected plants to (rot) a laboratory to identify the pathogen  Infection and Response part 3 – Plant disease (Biology HT) Healthy plants need mineral ions. Nitrate ions are needed in protein synthesis and hence growth. Horticulturists use knowledge about the effect of ion deficiencies to supply plants with optimum conditions. Nitrate ions = healthy growth Lack of nitrate = stunted growth Magnesium = healthy chlorophyll Lack of magnesium = chlorosis (yellowing of leaves due to lack of chlorophyll)  Infection and Response part 3 – Plant disease (biology only ) video l ca Ph ni ys ha ica ec l M Thick waxy layers, tough Plants have Touch can make cellulose cell walls and several ways of Mimosa leaves bark defend the plant defending suddenly curl which from pathogen entry frightens animals themselves from pathogens and to deter herbivores. M l ica ec em Antibacterial and ha Ch poisonous chemicals n ica Thorns make plants are found in many l painful to be eaten plants like witch hazel. QuestionIT! Infection and Response Part 3 Plant Disease (biology HT only)  Infection and Response part 3 – QuestionIT 1. Name 3 ways you can detect that a plant is diseased. 2. Copy and complete the table below: Type of plant What is the plant Describe the defence being used defence used being defended from? (Mechanical, physical or chemical) Herbivores eating it Thorns or hairs Chemical The chemical released is antibacterial Herbivores and Dead bark coating which falls off pathogen entry Physical Insects such as aphids  Infection and Response part 3 – QuestionIT 3. Describe why nitrate ions are very important for plants. 4. What is chlorosis and how can it be prevented? 5. Why would a test kit containing monoclonal antibodies be useful to detect plant disease? AnswerIT! Infection and Response Part 3 Plant disease (biology only)  Infection and Response part 3 – AnswerIT 1. Name 3 ways you can detect that a plant is diseased. leaf spots/discolouration, growths, malformed stems or leaves, presence of pests, stunted growth, areas of decay (rot) 2. Copy and Type of complete plant defence the table What below: is the plant Describe the defence being used used being defended (mechanical, physical against? or chemical) Mechanical Herbivores eating it Thorns or hairs Chemical Pathogens/bacteria The chemical released is Herbivores/animals antibacterial or poisonous Physical Herbivores and Dead bark coating which falls pathogen entry off Physical Insects such as Waxy cuticle/cellulose cell aphids walls are hard to penetrate  Infection and Response part 3 – AnswerIT 3. Describe why nitrate ions are very important for plants. Nitrate is crucial for protein synthesis and hence growth. Without sufficient nitrate ions, the plant would be stunted. 4. What is chlorosis and how can it be prevented? Chlorosis is the yellowing of the leaves. It can be prevented by providing the plant with magnesium. 5. Why would a test kit containing monoclonal antibodies be useful to detect plant disease? The monoclonal antibodies can be used to detect a particular chemical which is only present in one type of pathogen. This would then show whether the plant was infected with this disease or not.