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Domain Bacteria and Domain Archaea Bacteria: Archaea BASIC CHARACTERISTIC of Both: Unicellular Heterotrophic or Autotrophic Prokaryotic
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Eubacteria “True Bacteria” Archaea “Ancient” - extremophiles - Thermophiles, - Methanogens (salt) (anaerobic waste removal) (Hydrothermal vents) - Halophiles
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How do Bacteria and Archaea differ? Domain Bacteria Structural: Peptidoglycan in cell wall Molecular: Simple RNA polymerases Domain Archaea Structural: No peptidoglycan in cell wall. Molecular: Complex RNA polymerase
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Gram staining is used to identify bacteria. Gram-negative bacteria have a thin layer of peptidoglycan and stain red/pink. Gram-positive bacteria have a thicker peptidoglycan layer and stain purple. –Stains the peptidoglycan layer. –Gram-positive = Stain color - purple, Thick peptidoglycan cell wall –Gram-negative = Stain color - Pink, Thin peptidoglycan cell wall + outer membrane. E. coli B.subtilis
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Why are some bacteria resistant to certain antibiotics? GRAM NEGATIVEGRAM POSITIVE
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How bacterial resistance occurs!
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Basic Bacterial Structure flagellum pili cell wall Nucleic Acid cell membrane Ribosome Plasmid
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Bacteria are Classified by Shape and Growth Pattern – Spirilla = spiral shaped – Bacillus = rod shaped – Coccus = spherical shaped - Diplo = pair - Strepto = chain - Staphylo = cluster
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Test yourself…Classify these bacteria? Streptobacillus Diplococcus Streptococcus Spirillus
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Genetic Variation in Bacteria Transformation – Bacterial picks up free DNA and adds it in to its own DNA. Conjugation –One bacteria transfers DNA to another. Mutation – Random change in a DNA sequence.
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How are Bacteria helpful? Benefit to Ecosystems Decomposition (CO2) Chemical Cycling Fix nitrogen in the soil (air to soil) Cyanobacteria (photosynthesis) Bioremediation – The use of organisms to remove or neutralize pollutants from a contaminated site Provide Nutrients: Digestion of food in gut Cheese, butter, yogurt, sauerkraut
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How are bacteria harmful? Pathogens: Cause Disease Scarlet Fever - Streptococcus pyogenesStreptococcus pyogenes Strep Throat – Streptococcus pyogenes Bacterial Meningitis - Neisseria meningitidisNeisseria meningitidis Lyme Disease - Borrelia burgdorferiBorrelia burgdorferi Produce toxins Botulism Clostridium botulinum The chemical used in botox Food Spoilage Antibiotic Resistance
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What do we use to fight infection? Antibiotics Vaccines Antiseptic
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Antibiotics Vs Vaccines Antibiotics only treat bacterial infections Given after someone is infected Prevents bacterial growth Vaccines treat viral or bacterial diseases Given prior to infection Is made up of a small dose of the pathogen Creates antibodies to fight future infections
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Antibiotic Sensitivity Antibiotic Sensitivity - the susceptibility of bacteria to antibiotic To test antibiotic sensitivity - Thin wafers containing an antibiotic are placed on an agar plate that is growing bacteria. The bacteria are can’t grow next to the antibiotic they are sensitive to.
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Zone of inhibition - area around antibiotic disc where bacterial growth is inhibited. Antibiotic Resistance - No clear zone (indicate antibiotic resistance) Antibiotic discs are identified by the letter on the top. AntibioticIdentifier Penicillin P ChloramphenicolC DoxycyclineD StreptomycinS CiprofloxacinCIP ControlCNTL
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Zone of inhibition P D C CIP S CNTL 2cm 4 cm 5 cm 4 cm 1 cm
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CIP S P CNTL D C 1 cm 2 cm 3 cm 4 cm 0 cm
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