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Prokaryotes

Prokaryotes. Archaea & Bacteria Domains C23, pp461-476. Prokaryotic facts. Most numerous organisms on Earth Earth’s earliest fossils (3.5 x 10 9 yrs old) Lack membrane-bound organelles rRNA analysis shows Archaea linked more to Eukaryotes than to Bacteria

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Prokaryotes

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  1. Prokaryotes Archaea & Bacteria Domains C23, pp461-476

  2. Prokaryotic facts • Most numerous organisms on Earth • Earth’s earliest fossils (3.5 x 109 yrs old) • Lack membrane-bound organelles • rRNA analysis shows Archaea linked more to Eukaryotes than to Bacteria • Generally have cell wall, cell membrane, cytoplasm with ribosomes, DNA, & small ions/ molecules

  3. Archaea vs. Bacteria • Cell walls • Bacteria have peptidoglycans. Archaea don’t. • DNA • Archaea have introns. Bacteria don’t. • Groups • A: Methanogens, halophiles, thermoacidophile • B: Bacilli, cocci, spirilla; gram-pos & gram-negative

  4. Bacterial Cell Characteristics, p468 • Capsule: protects & aids in attachments • Cell wall: protects & gives shape • Cell membrane: control passage in/out of cells • Plasmid: carries genes in small DNA loop • Endospore: contains DNA; thick-coated • Pilus: attachment during conjugation • Flagellum: propels cells • Gram-neg outer membrane: deflect antibiotics

  5. Bacteria Nutrition, p469 • Autotroph • Photoautotroph (uses sunlight; gets C from CO2) • Chemoautotroph (gets energy from inorganic cpd; gets Carbon from CO2) • Heterotroph • Photoheterotroph (uses light energy but get Carbon from other organisms • Chemoheterotroph (gets energy & C from other organisms)

  6. Prokaryotic Reproduction, p471 • Single circular loop of DNA is copied • Binary fission yields 2 identical daughter cells • Exchanging DNA • Transformation • Gets DNA from its outside environment • Conjugation • Gets DNA from other prokaryote via sex pilus • Transduction • Virus copies piece of host DNA & transfers it to others

  7. Prokaryotic Habitats, p470 • Obligate anaerobes = no O2 allowed • Facultative anaerobes = + O2 is OK • Obligate aerobes = O2 necessary • Psychrophilic = cold-loving (0oC – 20oC) • Mesophiles = average (20o-40oC) • Thermophiles = hot-loving (45o- 110oC) • Acidophiles = pH at or below 6.0 • Most prefer neutral pH range of 6.5 – 7.5

  8. Bacterial disease, p472 • Disease • Anthrax • Botulism • Tetanus • Cholera • Gonorrhea • Dental caries • Food poisoning • Lyme disease • Bacterium • Bacillus anthracis • Clostridium botulinum • Clostridium tetani • Vibriocholerae • Neisseriagonorrhoeae • Streptococcus mutans • Salmnellatyphimurium • Borreliaburgdorferi

  9. Bacteria in Industry • Foods • Fermentation  buttermilk, sour cream, yogurt • Cheeses, sauerkraut, pickles, kimchi, coffee, soy • Medicine • Acetone, acetic acid, enzymes, antibiotics, insulin • Agriculture • Endotoxins as insecticides • Bioremediation = degrade petroleum

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