15/09/2015 Unit B2 Keeping Healthy

15/09/2015 Lesson 1: Microbes Lesson objectives: 1)To be able to list at least 4 ways through which microbes can enter our bodies 2) To be able to list 4 natural barriers the human body has to defend against microbes 3) To be able to state why microbes get past our first line of defence

Unit B2: What are microbes? STARTER Try and define a microbe in your own words. 15/09/2015

Microbes Microbes are micro organisms that are too small to be seen. A pathogen is a microbe that can cause diseases if it enters the body: …or other natural openings… They can be breathed in through the mouth or nose They can enter through cuts or bites in the skin or just by touching something They can be ingested (eaten) through the mouth

15/09/2015 Microbes: our defence against them Our bodies have many defence mechanisms against invading microbes: If our skin is cut platelets seal the wound by clotting The breathing organs produce mucus to cover the lining of these organs and trap the microbes The skin acts as a barrier Stomach produces stomach acid Tears contain an enzyme that kills bacteria

How quickly do microbes grow during our school ? 15/09/2015

How many antibacterial or antimicrobial products can you think of?

15/09/2015 Antibacterial products we see on T.V.

15/09/2015 Agar petri dish

15/09/2015 Aim: Aim: To investigate the effect of antimicrobial products Equipment: Method: - what did you do? –Dependent variable (the factor you will record/measure) –Independent variable (the factor you will change) –Control (what factors will you keep the same?) Draw diagram of how you made up the petri dish Results: Draw a results table to record what you see next lesson. Conclusion: Evaluation: Was it a fair test? Did you get any strange results and why?

15/09/2015 Additional points for your conclusion….. C/B Grade Explain how dilution affects the activity of antibacterial chemicals and why. A Grade Explain how do you think the concentration of cosmetic products and medicines is calculated to give maximum benefit from the minimum amount of chemical.

15/09/2015 Additional points for your conclusion….. C/B Grade How dilution affects the activity of antimicrobial chemicals and why. A Grade How do you think the concentration or dosage in cosmetic products and medicines is calculated to give benefit from the minimum amount of chemical (if a range of bacterial species has been used) A* Grade Do you think antimicrobial chemicals are more effective against some microbes than others? What other factors could change the effectiveness of these chemicals?

15/09/2015 Title: What are the different ways in which microbes spread & how fast? What are the different ways through which microbes can spread? –Water –Air –Food –Touch –Animals –Sex WAFTA’S!

15/09/2015 What are the different ways in which pathogens spread?

15/09/2015 How fast can bacteria grow in a school day? Worksheet

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If bacteria can grow that fast….then why isn't the earth covered with bacteria?!?!!

15/09/2015 The main reason may be that conditions are rarely optimum! Bacteria also can’t “hunt” for food…so existing nutrients eventually run out.

15/09/2015 Graph showing how bacteria grow in a sealed container Steady phase – growth of new bacteria equals death of old bacteria Fastest increase in growth – bacteria divide every 20 mins. More bacteria die than are made. Growth gets going.

15/09/2015 ‘Outbreak’ scenario You have been notified of an unidentified microbe. How will you find out how it spreads? How will you find out how fast it spreads?

15/09/2015Disease A disease is any condition where the body isn’t working as it should. This could be caused by a malfunction in the body (as with diabetes), or it could be caused by the two types of MICROBE: VirusesBacteria 1/1000 th mm big Living cells (some are harmless) Grow very quickly Affected by antibiotics Examples: food poisoning, tetanus, sore throats 1/1,000,000 th mm big Genetic info inside a protein coat Not affected by antibiotics Release poisons Examples: colds, flu, polio, chicken pox

15/09/2015Fungi Fungi are another form of microbe. There are many different varieties ranging from bread mould to mushrooms.

15/09/2015 How does our body help to keep us to fight pathogens?

15/09/2015 Title: What happens when microbes enter our body? What’s the name of the cells that defend our bodies against pathogens?

15/09/2015 Today’s lesson To be able to describe, in detailed steps, how our immune system fights microbes To be able to explain how our immune system works when a microbe attacks for the 2 nd time. Produce a basic storyboard with steps on how our defence system works.(C/B grade) Write own key words Annotated diagrams on storyboard using the correct scientific terms (B/A grade)

15/09/2015 Pathogens usually have ‘antigens’ on their surface which is recognised by our immune system ‘antibodies’ Antigens cause our immune system to produce ‘antibodies’

15/09/2015 Fighting disease If microbes do enter our body they need to be neutralised or killed. This is done by WHITE BLOOD CELLS: White blood cells do 3 things: 1)They produce antibodies to neutralise the microbe 2)They eat the microbe 3)They produce antitoxins to neutralise the poisons produced by microbes

15/09/2015 The type of WBC that engulf the pathogen are called phagocytes The parts that extend to engulf the pathogen is called a pseudopod and are like ‘false legs’

15/09/2015 phagocyte

15/09/2015 Your task Create a storyboard which describes how our WBC’s fight pathogens.

15/09/2015 Producing antibodies Step 1: The white blood cell “sees” the antigen (microbe) Step 2: The cell produces antibodies to “fit” the antigen Step 3: The antibodies fit onto the antigens and cause them to “clump” Step 4: The antigens are “eaten” by the white blood cells You’re going down

15/09/2015 How do our bodies make us ‘immune’ after we get a disease just once?

15/09/2015 Re-cap: antigen/antibody action

15/09/2015 How would you draw a graph of what happens to antibody production?

15/09/2015Graph 1.How no. of antibodies change during the first 20 days of exposure to a pathogen (0 – 20 days) 2. How the no. change after your body has destroyed the pathogen (25 – 40 days) 3. How the no. of antibodies change on the 2 nd exposure to the same pathogen (Day 65)

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Steps of immunity

15/09/2015 What do you think is the difference between natural immunity and artificial immunity?

15/09/2015 Fighting disease NATURAL IMMUNITY This is when antibodies are produced by a person when needed or they are passed on by the mother during pregnancy. ARTIFICIAL IMMUNITY A vaccine with dead microbes is injected – the body is “tricked” into producing antibodies ready for the real thing. This is called PASSIVE IMMUNISATION

15/09/2015 Using Antibiotics Antibiotics can be used to kill bacteria. However, there are two problems: 1) Overuse of antibiotics can lead to bacteria becoming resistant 2) Antibiotics have no effect on a virus, like the common cold. A virus must be allowed to “run its course”.

15/09/2015 What problems do you think there might be with antibiotics in fighting disease? Do you think their effect lasts for ever? Can they treat all infectious diseases?

15/09/2015 Antibiotic resistance Antibiotics are made naturally by bacteria/fungi to destroy other micro- organisms. E.g. penicillin However – bacteria become resistant to an antibiotic. So new antibiotics have to be developed every time a bacteria becomes resistant.

15/09/2015‘Superbugs’ Superbugs are bacteria that are resistant to all know antibiotics – except one. But we don’t know how long that will last! Just a tiny change in one gene can cause a bacteria to mutate – and it can become a superbug.

15/09/2015 One superbug by itself won’t do much damage – but if it reproduces quickly then a large bacteria population could be resistant to an antibiotic.

15/09/ things increase the risk of antibiotic resistance: 1.People taking antibiotics they don’t really need. 2.People not finishing their course of antibiotics

15/09/2015 Write down at least 3 ideas of how we can stop superbugs spreading in our hospitals

15/09/2015 How can we stop the superbugs? 1.Developing new antibiotics 2.Better hygiene in hospitals to reduce risk of infection 3. Only prescribing antibiotics when a person really needs them 4. Education! Making sure people understand why it’s important to finish their course of antibiotics

15/09/2015 Re-cap of last lesson: antibiotics

15/09/2015 Title: How do vaccinations work? Key words

15/09/2015 So why is it taking so long to find a cure for HIV?

15/09/2015Hmmmm…. HIV is an uncommon type of virus called a retrovirus, and drugs developed to disrupt the action of HIV are known as antiretrovirals or ARVs. These come in a variety of formulations designed to act on different stages of the life-cycle of HIV.

15/09/2015 The AIDS virus mutates rapidly, which makes it extremely skilful at developing resistance to drugs. To minimize this risk, people with AIDS are generally treated with a cocktail of ARVs that attack the virus on several fronts at once. ARVs have proved very effective at treating people with AIDS. But they are not a cure. If treatment is discontinued the virus becomes active again, so a person on ARVs must take them for life.

15/09/2015 Title: Vaccination policy By the end of the lesson…Grade WILF Outline the key features of a vaccination policy C Identify different viewpoints that people may have B Challenge /Analyse strategies and viewpoints Produce counter arguments based on logical/or empathetic grounds A A*

15/09/2015 MMR vaccine

15/09/2015 Your task 1.Look at the MMR vaccine article in textbook. 2.Use the information to fill in your table.

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Writing plan: 1.Outline in general what a vaccine policy is and how it may be implemented 2.Produce a logistic plan of how you would carry one out. 3.Give a list of benefits to the public of a vaccination policy. 4.Outline 2 or more areas of society that may benefit from a vaccine policy. 5.Give 2 differing points of view that parents may have. Try to explain their reasons. 6.Explain why it is important that a large majority of the population is vaccinated against a contagious disease. 7.Evaluate in your opinion the rights of a person to refuse a vaccine with the right of the general public to be protected