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Microorganisms Bacteria and Viruses Chapter 19
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Review Prokaryote and Eukaryote Cell Structure and Function Classification
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Prokaryotes Classifying Prokaryotes Kingdoms Eubacteria Archaebacteria
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Kingdom Archaebacteria 3.5 billion years ago Characteristics Unusual lipids in their cell membrane DNA similar to eukaryotes No peptidoglycan in their cell wall
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Categories of Archaebacteria Methanogens Use hydrogen gas Reduce carbon dioxide to methane Extremophiles Thermophiles (60-80 o C) Halophiles Non-extremophiles Same environment as eubacteria, DNA is unique
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Kingdom Eubacteria Shapes Bacilli Straight rod Cocci spherical Spiral Long and spiral Groupings Staph- graph cluster Strep - chain
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Gram Staining Bacteria Steps: 1. crystal violet 2. iodine stain 3. alcohol wash 4. safranin Positive = purple Negative = pink
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Gram Positive Bacteria Gram Negative Bacteria Mixed Bacteria
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What Gram Indicates Difference in the cell wall (peptidoglycan) Why Gram Stain? Determines antibiotic efficiency Indicates different toxins React to disinfectants differently
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Structure of Bacteria
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The Biology of Eubacteria Cell Wall Peptidoglycan protection Cell membrane and Cytoplasm Lipids and enzymes surface area ribosome
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Pili Hair-like outgrowths for attachment Endospore Thick wall around the chromosome during unfavorable growth conditions Resistant Live for decades! Bacillus and Clostridium strains
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Movement Flagella Run and Tumble slime Obtaining Energy Autotrophs Heterotrophs
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Releasing Energy Obligate anaerobes Clostridium botulinum Facultative anaerobes Escherichia coli Obligate aerobes Clostridium tuberculin
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Reproduction and Growth Binary Fission Identical clones Transformation Transduction Conjugation Two living bacteria bind and one transfers genetic information to the other through a sex pili Creates genetic diversity
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Bacteria in Nature Decomposers Recycle nutrients in the ecosystem Sewage treatment Nitrogen Fixers Converting nitrogen gas into a usable form for the production of amino acids
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Bacteria and Disease Pathology – study of disease Pathogens Damage to tissues Release of toxins Exotoxins (Gram+, Clostridium tetani) Endotoxins (Gram-, Escherichia coli)
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Modes of Transmission 1. Airborne legionellosis, pertussis, diphtheria 2. Animal lyme disease, bubonic plaque 3. Direct Contact gonorrhea, anthrax 4. Food or Waterborne salmonella, cholera, diarrhea
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Antibiotics Drugs to combat bacteria only! Complete entire course of medication Water is essential Check Gram +/- status Resistance Abuse and Misuse Evolution mutations
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Human Uses of Bacteria Soil Food Industry Biotechnology
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Viruses Latin word for POISON What is a virus? Wendell Stanley Not living! Nucleic acid and protein Cause infection Take over the machinery of their host Tobacco Mosaic Virus
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Viruses are not members of the Six- Kingdom System of Classification Detached Fragment of a genome Infect all taxonomic levels! They are highly specific
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Characteristics Size Smallest biological particle 17 nm to 1000 nm Structure Not cellular Nucleic acid (DNA or RNA) Protein coat Shape Helical or isometric
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Bacteriophage Infect bacteria DNA Example: T4 phage
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Viral Infection Lytic Cycle - Virulent 1. Attachment 2. Entry 3. Replication
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4. Assembly 5. Release lysis!
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http://www.cat.cc.md.us/courses/bio141/le cguide/unit2/viruses/adlyt.html http://www.cat.cc.md.us/courses/bio141/le cguide/unit2/viruses/adlyt.html
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Lysogenic Cycle - temperate
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Lysogenic Cycle Stages 1. Attachment 2. Injection 3. Integration of Prophage 4. Cell multiplication 5. Conversion * May stay dormant for many a unknown period of time
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http://www.cat.cc.md.us/courses/bio141/le cguide/unit2/viruses/lysosum.html http://www.cat.cc.md.us/courses/bio141/le cguide/unit2/viruses/lysosum.html
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Viruses and Disease Vaccine protection Attenuated Inactivated Oncogenic viruses Retroviruses Prions Stanley Prusiner Scrapie, BSE, CJD
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Lysogeny of HIV Typical animal virus Cause of Acquired Immune Deficiency Syndrome (AIDS) US since 1981 Virus closely related to a chimpanzee virus Persons die from opportunistic infections
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