Bacteria 1

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Bacteria 1

  1. 1. Bacteria
  2. 2. Quick Quiz True or False 1. 600 different kinds of bacteria live on your skin. True 2. Saliva contains 30 different kinds of bacteria. False; 6 3. Most bacteria multiply using the process of binary fission. True 4. You can see, taste, and smell bacteria. False; cannot see with naked eye 5. Leaving foods at room temperature will slow bacterial growth. False; Place in cold environments 6. There are more microbes on your body than there are humans on the entire planet. True.
  3. 3. True / False con’t 7. Bacteria help our bodies with digestion and produce True: E. coli makes vitamin K and B12 8. Bacteria are used to make chocolate. True; it helps digest the hard outer covering of the bean 9. Only 50% of all bacteria are helpful. False; 99% 10. The four shapes of bacteria are circular, square, rod, and spiral. False; No square
  4. 4. Prokaryotes vs. Eukaryotes Prokaryotes  Eukaryotes  No true Nucleus  Membrane bound  No membrane nucleus bound organelles  Membrane bound  Small organelles  Simple  Larger  Evolved 3.5 bya  Complex  Evolved 1.5 bya
  5. 5. Bacteria Can be found almost everywhere on Earth. Earliest known fossils 3.5 bya Oldest group of organisms All bacteria are prokaryotes 2 main groups (kingdoms) Eubacteria Archaebacteria
  6. 6. EUBACTERIA / TRUE BACTERIA  Most common today  Cause disease & decay  Cell wall protects and determines shape.  Contains peptidoglycan (carbohydrate)  Example:  E. coli= live in intestines of humans
  7. 7. Archaebacteria “ancient bacteria”  Live in extreme environments  Direct ancestors of eukaryotes  Examples:  Methanogens= oxygen free environments thick mud and digestive tracks.  Halophites= Salty environments Utah’s Great Salt Lake
  8. 8. Prokaryotes are Identified Bytheir… 1. Shape 2. Chemical Nature 3. The way they move 4. The way they obtain energy.
  9. 9. Shapes of Bacteria Spherical (round / cocci)  Streptococcus aureus Spiral (sprilla)  Trepnema pallidum (syphilis) Rod-Shaped (bacillus)  Escherichia coli
  10. 10. Shapes of Bacteria
  11. 11. Structure of Bacteria
  12. 12. Cell Walls of Bacteria Gram staining helps distinguish between the 2 different types of bacteria. Gram +  Thicker peptidoglycan walls  Keeps dark stain  Appears purple Gram –  Thinner cell wall  Appears pink
  13. 13. Gram Staining- Use to diagnose& treat disease Gram +  Gram – Harmless Harmful Important  Unaffected by in food and many dairy antibiotics. Can’t penetrate industries cell wall  Turns purple  Turns pink  Ex)  Ex) E. coli Streptococcus pneumonia
  14. 14. Movement 1) Flagella- whip like structures 2) Lash, snake, or Flagella Position spiral 3) Glide along slime
  15. 15. Obtaining Energy Heterotrophs-  Getenergy by consuming organic molecules made by other organisms. Autotrophs-  Make their own food from inorganic molecules.
  16. 16. Autotrophs Photoautotrophs Use sunlight to convert carbon dioxide & water to carbon compounds and oxygen. Ex: Cyanobacteria Chemoautrotrophs Use energy from chemical reactions to make organic carbon molecules Live in darkness; ocean bottoms.
  17. 17. Releasing Energy Obligate aerobes- require oxygen TB Mycobacteruim tuberculosis Obligate anaerobes- NO oxygen Clostridium botulinum (canned food) Facultative anaerobes- do not require oxygen but are not killed by it. E. coli (large intestines and canned food)
  18. 18. Growth & Reproduction Some bacteria can divide in ~20 min 3 ways bacteria divide  1) binary fission  2) Conjugation  3) Spore formation
  19. 19. Bacteria Reproduction Binary fission  Asexual – clones  Splitting in ½  1st growth  2nd DNA is copied  3rd splits into 2 cells
  20. 20. Conjugation Sexual reproduction Hollow bridge forms between 2 bacteria cells Exchange of DNA Result: increase in genetic variation
  21. 21. Spore Formation Formed in unfavorable conditions Can keep for months or years Produces a thick internal wall that encloses the DNA & cytoplasm Dangerous
  22. 22. Limiting Factors in BacteriaReproduction (Growth)  Nutrients  temp (freeze/ pasteurization)  Moisture  pH  Time  Sanitizing
  23. 23. Importance of Bacteria 1. Producers 2. Decomposers 3. Human uses
  24. 24. 1) Producers / Nitrogen Fixers  Plants & animals depend on bacteria for nitrogen  Need N2 to make amino acids.  N2 makes up ~ 80% of Earth’s atm  Plants take N2 convert it to NH3 (ammonia) this process is known as nitrogen fixation is done by bacteria.
  25. 25. 2) Decomposers Bacteria recycle nutrients Trees die -> Bacteria break down -> Nutrients are returned to the soil -> Process repeats
  26. 26. 3) Human Uses Food- cheese, yogurt Beverages- wine, milk Industry- digest petroleum, clean up oil spills Medical uses- synthesize drugs E. coli- makes vitamins the body cannot make Etc.

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