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Biology II

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  1. Biology II Diseases caused by Bacteria and Viruses

  2. Diseases by Bacteria and Viruses • Pathogens- Disease causing agents • Bacterial Disease • Viral Disease

  3. Bacteria • Most bacteria in out body are harmless • A few species cause infectious diseases • Cholera • Syphilis • Anthrax • Leprosy • Bubonic plague

  4. Diseases caused by Bacteria • How does bacteria produce disease? • Damage the cells and tissues by breaking down the cells for food • Releasing toxins (poisons into the body)

  5. One of the most common bacteria is streptococcus pyrogenes which is strep throat. • Other bacteria diseases • Salmonella- the bacteria that causes food poisoning in humans • E. Coli- bacteria that live in intestins, and are the sources of many food poisoning outbreaks

  6. Controlling Bacteria • Sterilization • Disinfectants • Proper food storage

  7. Antibiotics • Antibiotics are chemicals which either kill bacteria or prevent their growth and reproduction • Bacteria and other microbes produce antibiotics to reduce competition from other organisms

  8. Penicillin was the first to be used to fight diseases • Two scientist Walter Florey and Ernst Chain determined how to use penicillin to treat disease in 1939 • The discovery of antibiotics revolutionized the treatment of disease

  9. How Antibiotics Works • Antibiotics effect bacteria, but not eukaryotic cells • Antibiotics attack bacteria in 5 ways • Damage the cell walls or prevent cells walls from forming • Damage the cell membrane • Prevent protein synthesis • Prevent DNA from being Copied • Interfere with bacterial Metabolism

  10. Diseases caused by Viruses • Viruses disrupt the body’s normal equilibrium • Cannot be treated with antibiotic • Viruses can infect humans and plants

  11. How do they Spread • Carried by blood sucking insects • Spread by coughing and sneezing • Passed from person to person contact • Sexual contact • Exposure to infected blood

  12. How to Eliminate the virus • Viral infections provoke an immune response- • This will eliminate the infecting virus • The immune system is made of white blood cells- the body’s army • Vaccines- are very specific to which virus they protect our body’s against

  13. Viruses and Disease • Adenovirus- virus that causes colds, spread through the air • Influenza- virus that causes flu; many different strains of this virus • Herpes simplex virus- virus that causes herpes infections • Bacteriophage- viruses that infect bacteria cells

  14. HIV/AIDS • HIV is the virus that cause AIDS. • HIV attacks the body’s immune system making it weak and prone to infection • It is hard to find a cure or vaccine for AIDS because it is constantly evolving and can live in a person’s cell for year

  15. Viruslike Partilces • Viroid – single stranded RNA molecules with no capsid • They cause diseases in plants • Infect cell and produce more viroid by disrupting the plant metabolism

  16. Prions- contain only protein; no DNA or RNA • They cause diseases in animals and humans • Prions clump and cause normal protein to clump with it- creating new prions