Ch. 19 – Importance of Bacteria!

1. Ch. 19 – Importance of Bacteria!

2. Used in food – yogurt, cheese, sauerkraut • Decompose dead things • E-coli in your stomach • Sewage treatment • Nitrogen fixation – convert nitrogen from air to a form that plants can use.

3. Bacteria & Disease: • Examples of disease caused by bacteria: • Bubonic Plague – carried by fleas on rats. • “Ring around the Rosie Pocket full of posies Ashes, Ashes We all fall down”

5. Escherichia coli (E-coli) • A whole family of bacteria, not all of which are harmful. • Good - Depend on E. coli in our intestines for Vitamin K and B • Bad - E-coli (0157:H7): symptoms: Bleeding, loss of water, kidney failure

6. Some Terms to know: • Pathogens– viruses and bacteria that are disease producing agents • Virulence – the ability to cause disease

7. 3 Steps to Disease • Contamination: pathogens are present… • Through air, food or water b. Direct contact (touch, body fluids, etc.) c. Contact with a carrier of a pathogen (tetanus [lockjaw] comes from bacteria found on soil particles)

8. Tetanus - medical condition characterized by a prolonged contraction of skeletal muscle fibers

9. 3 steps continued… • Infection – pathogens multiply in body • Disease – disturbance in the healthy body, so it can no longer carry out its normal functions.

10. Bacteria cause disease in one of these 2 ways: • Break down cells to use as a food source. (Mycobacterium tuberculosis) • Release Toxins (E. coli) M. tuberculosis - destroys lung tissue; can enter blood stream & destroy other tissue.

11. Coping with Disease: • Immunity – resistance to a pathogen that is acquired or inherited. • Antibodies – proteins that the body makes to destroy pathogens. • Antibiotics – drugs that attack and destroy bacteria. (before these, people died of things like strep throat!)

12. Major Antibiotic: • Penicillin • Alexander Fleming 1928 discovered by accident in lab • A type of mold • Different types (amoxicillin, etc. come from different forms of the Penicillin fungi – mold)

13. Controlling Bacteria: • Sterilization – heat of chemicals to kill bacteria • Bacteria cannot survive high temperatures for very long • Examples: Autoclave at the vet, dentist, doctors office, etc.

14. Disinfectants – chemical solutions to reduce the number of bacteria • Examples: Antiseptics, Antibacterial products (soaps, cleansers, kitchen utensils)

15. Controlling bacteria continued… • Soap – wash bacteria away; may be good enough • Food preservation – salt, vinegar, sugar, heat, low temperatures (refrigeration – doesn’t kill just slows growth!)