AQA Biology: Pathogens and disease
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AQA biology presentation on pathogens and disease. Please also see youtube video of this being presented here: https://www.youtube.com/watch?v=Wu1Lyn8GjSo
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AQA Biology: Pathogens and disease
- 2. What should I know? • Pathogens include bacteria, viruses and fungi • Disease can occur from pathogens entering the body via an interface • Interfaces include: digestive and gas exchange systems • Pathogens cause disease by producing toxins or damaging host tissues • Lifestyle can affect health • Risk factors for CHD and cancer
- 3. What it boils down to… • Pathogens • Pathogen entry into the body • How a pathogen causes damage • Lifestyle factors that increase risk of CHD • Lifestyle factors that increase risk of cancer
- 4. Pathogens
- 5. • Viruses • Bacteria • Fungi • A pathogen is a microorganism that gains entry, colonises the tissues, resists the defences and causes damages to the tissues of the host
- 6. How do they get in?!
- 7. • Through interfaces… • These include respiratory system (droplets in the air) • E.g. TB and Flu • Digestive system (food and water) • E.g. Cholera
- 8. We don’t get ill all the time… • Our body has defences to prevent pathogens entering • Mucous - covers exchange surfaces and forms a sticky barrier that is hard to penetrate • Enzymes - break down pathogens • Stomach acid - very strong and has a low pH so kills pathogens
- 9. How do they make us ill?
- 10. They cause damage! • They act by damaging host tissues - theres loads of them so the sheer numbers burst cells open • Viruses also act by stopping DNA and RNA synthesis in cells • They produce toxins - chemicals that cause damage • E.g. cholera produces a toxin that leads to diarrhoea
- 11. Lifestyle also plays a role in disease…
- 12. Factors that increase the risk of Cancer • Smoking • Diet (if it’s high in fat) • Obesity • Low amount of physical activity • High sunlight exposure
- 13. Factors that increase the risk of CHD • Smoking • High blood pressure • High blood cholesterol • Obesity • High salt diet • High saturated fat diet • Low amount of physical activity
- 14. Thanks for watching! notes and more available at http://myrevisionnotes.blogspot.com