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Identifying and Classifying Bacteria

Identifying and Classifying Bacteria. What is a prokaryote?. Cells that lack a true nucleus . Cells that lack membrane-bound organelles . Most surrounded by a cell wall. Many secrete a protective slime capsule . How big is a prokaryotic cell?. 1- 5 micrometers (1 millionth of a meter).

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Identifying and Classifying Bacteria

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  1. Identifying and Classifying Bacteria

  2. What is a prokaryote? • Cells that lack a true nucleus. • Cells that lack membrane-bound organelles. • Most surrounded by a cell wall. • Many secrete a protective slime capsule.

  3. How big is a prokaryotic cell? • 1- 5 micrometers • (1 millionth of a meter)

  4. Classification • Archaebacteria vs Eubacteria

  5. Archaebacteria • Surrounded by a cell wall lacking peptidoglycan. • Live in extreme conditions

  6. Examples of Archae • Methanogens: convert H2 and CO2 into methane gas for energy • Halophiles: love salt • Thermoacidophiles: love heat and acid

  7. Eubacteria: • Surrounded by a cell wall made of peptidoglycan. • Example: rhizobium- nitrogen–fixing bacteria

  8. Identifying Prokaryotes 1. Shape: • Coccus – spherical • Bacillus – rod-shaped • Spirillum – spiral • Vibrio – comma shape

  9. Bacillus Coccus Vibrio Spirillum

  10. Cocci and Bacilli may group together Prefixes for arrangements: Diplo – two Ex. Diplococcus

  11. Strepto – chain Streptococcus Streptobacillus

  12. Staphylo - clustered Staphylococcus

  13. 2. Motility: ability to move • Flagella: whip-like structure used to propel bacteria • Slime: glide along slime secretion • Spiral motion: cork-screw motion (spirillum)

  14. 3. Metabolism: Oxygen or NOT • Obligate Aerobes: Need oxygen • Obligate Anaerobes: cannot live in oxygen • Facultative anaerobes: can live with or without oxygen

  15. 3.Metabolism: Obtaining Energy Autotroph vs. Heterotroph • Photoautotroph- uses light energy for photosynthesis • Chemoautotroph- uses energy from inorganic chemicals for chemosynthesis

  16. Photoheterotrophs- uses photosynthesis and eats organic compounds • Heterotroph – consumes organic compounds

  17. review • What role do chemosynthetic bacteria have in the ecosystem? • http://www.youtube.com/watch?v=4lmwbBzClAc&NR=1

  18. Bacterial Reproduction

  19. BACTERIA REPRODUCITON • Bacteria reproduction is Asexual • Bacteria reproduce though a process called binary fission

  20. Asexual: Binary fission • Circular DNA replicates • Cell membrane and cell wall divide • Identical daughter cells separate

  21. How fast does this happen? • http://www.youtube.com/watch?v=gEwzDydciWc&feature=related • approximately every 20 minutes

  22. Disease • Pathology is the study of disease. • Pathogens: organisms that cause disease.

  23. For example • Clostridium tetani secretes an exotoxin that causes tetanus. • Tetanus causes stiffness in muscles. • Clostridium botulinumproduces a very powerful exotoxin that causes the fatal disease, botulism. • 1 g of botulism toxin can kill 1 million people.

  24. For example: • Most species of Salmonella, are endotoxin producing bacteria. • Salmonellatyphi, causes typhoid fever.

  25. Antibiotics • Antibiotics interfere with the bacteria’s cellular activities.

  26. For example: • Penicillin: blocks the building of the cell wall. “Accidently” discovered by Alexander Fleming in 1920s • Tetracyline: blocks protein synthesis.

  27. Where do antibiotics come from? • Antibiotics are naturally made by some fungi and bacteria. • Some are made synthetically in labs. • But most used in treatment still come from bacteria.

  28. Antibiotic-Resistance • Bacteria can quickly adapt to their environment because of their rapid rate of reproduction.

  29. Which diseases are preventable by better sanitation practice? So….. Wash your hands!!!! • Cholera • Salmonella • Tetanus • Staph

  30. Good bacteria • Use to make antibiotics • Used to “Sour” food - Sour cream, pickles, cheese, sour krout, yogurt • Digestive bacteria – help to break down proteins

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