Microorganism And Disease
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Microorganism And Disease






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Microorganism And Disease Presentation Transcript

  • 1. Unit 3: It's a Small World Microorganisms and Disease
  • 2. What Do You Think? When you “catch a cold,” what is it that infects your body?
  • 3. Germ Theory  Idea that microorganisms can and are the cause of many diseases  Originally proposed back in 1020 A.D. and built upon by many different scientists  Microorganisms were first observed by Anton van Leeuwenhoek  Louis Pasteur, a French chemist, helped to disprove another competing theory and his
  • 4. Germ Theory  Joseph Lister, an English surgeon, was one of the 1st to realize the importance of germ theory  He used chemicals on wounds to kill germs  Also made sure that everything that touched his patients was washed in a chemical solution so that it was free of germs
  • 5. Antiseptics = Disinfectants?  Antiseptics are for use on people  Disinfectants are for use on objects and surfaces.
  • 6. Robert Koch  1st to actually demonstrate that microorganisms do cause disease  Studied anthrax  While investigating the disease, he developed a set of rules for proving that a microorganism is the cause of a specific disease.  These rules are called Koch’s postulates and they are a good example of the scientific method.
  • 7. Koch’s postulates 1. The microorganism must be found in abundance in all organisms suffering from the disease, but not in healthy organisms. 2. The microorganism must be isolated from a diseased organism and grown in pure culture.
  • 8. Koch’s postulates 3. The cultured microorganism should cause disease when introduced into a healthy organism. 4. The microorganism must be reisolated from the inoculated, diseased experimental host and identified as being identical to the original agent.
  • 9.  List as many different diseases as you can.
  • 10. Diseases  2 types of disease  Noninfectious diseases: diseases that are not spread from one person to another  Infectious diseases: diseases that can be passed from one living thing to another
  • 11. What causes disease?  Noninfectious diseases can be caused by many different factors. Smoking, lack of physical activity, and a high-fat diet can greatly increase a person’s chances of getting many noninfectious diseases.  Infectious diseases are caused by pathogens
  • 12. Think, Pair, Share  How is an infectious disease different from a noninfectious disease?
  • 13. Did You Know?  Before the mid-1800’s, doctors and surgeons rarely washed their hands before surgery.  This was because pathogens were not known about  Many people believed that if someone got a disease it was because they were being punished
  • 14. Pathways to Pathogens  Look at p.S68 in your textbook. What are two ways that infectious diseases are spread?
  • 15. Pathways to Pathogens  There are many ways pathogens can be passed from one person to another. Being aware of them can help you stay healthy. 1. Through the air: a single sneeze releases thousands of tiny droplets of moisture that can carry pathogens
  • 16. Pathways to Pathogens 2. Contaminated objects: person who is sick may leave bacteria or viruses on objects such as doorknobs, keyboards, drinking glasses, towels, or combs. 3. Person to Person: may become infected with some illnesses by kissing, shaking hands, or touching the sores of an infected person
  • 17. Pathways to Pathogens 4. Animals: some pathogens are carried by animals; humans can get ringworm from handling an infected dog or cat. Also, ticks can carry bacteria that cause Lyme disease. 5. Food and water: water lines can break or treatment plants can become flooded allowing microorganisms to enter the public
  • 18. Brain Food  In developing countries, 80% of diseases are related to contaminated drinking water.
  • 19. Inferring Relationships  Why might the risk of infectious disease be high in a community that has no water treatment facility?
  • 20. Checkpoint  Jackie cut up raw meat on her kitchen counter. If her brother makes a sandwich on the same counter later, how could he come in contact with a pathogen?
  • 21. Causes of Infectious Disease  Bacteria are one kind of microorganism that can cause an infectious disease. Can affect the human body in different ways  Bacteria can kill cells and tissues  Other bacteria do damage by releasing toxins
  • 22. Causes of Infectious Disease Viruses  Smallest of disease-causing microorganisms  Even the largest virus can just barely be seen with a light microscope  Common cold, influenza, warts, rabies, AIDS, Ebola
  • 23. Causes of Infectious Disease Protozoans  Malaria and sleeping sickness Fungi  Cells of the fungus enter the body through the digestive or respiratory system  Athlete’s foot and ringworm
  • 24. Think, Pair, Share  What are the four causes of infectious disease?  Which cause involves toxins?  Which cause is at fault when you have the flu?