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Microorganisms

Microorganisms. Bacteria and Viruses Chapter 19. Review Prokaryote and Eukaryote Cell Structure and Function Classification. Prokaryotes. Classifying Prokaryotes Kingdoms Eubacteria Archaebacteria. Kingdom Archaebacteria 3.5 billion years ago Characteristics

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Microorganisms

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  1. Microorganisms Bacteria and Viruses Chapter 19

  2. Review • Prokaryote and Eukaryote • Cell Structure and Function • Classification

  3. Prokaryotes • Classifying Prokaryotes • Kingdoms • Eubacteria • Archaebacteria

  4. Kingdom Archaebacteria • 3.5 billion years ago • Characteristics • Unusual lipids in their cell membrane • DNA similar to eukaryotes • No peptidoglycan in their cell wall

  5. Categories of Archaebacteria • Methanogens • Use hydrogen gas • Reduce carbon dioxide to methane • Extremophiles • Thermophiles (60-80oC) • Halophiles • Non-extremophiles • Same environment as eubacteria, DNA is unique

  6. Kingdom Eubacteria • Shapes • Bacilli • Straight rod • Cocci • spherical • Spiral • Long and spiral • Groupings • Staph- graph cluster • Strep - chain

  7. Gram Staining Bacteria Steps: 1. crystal violet 2. iodine stain 3. alcohol wash 4. safranin Positive = purple Negative = pink

  8. Gram Positive Bacteria Gram Negative Bacteria Mixed Bacteria

  9. What Gram Indicates • Difference in the cell wall (peptidoglycan) • Why Gram Stain? • Determines antibiotic efficiency • Indicates different toxins • React to disinfectants differently

  10. Structure of Bacteria

  11. The Biology of Eubacteria • Cell Wall • Peptidoglycan • protection • Cell membrane and Cytoplasm • Lipids and enzymes • surface area • ribosome

  12. Pili • Hair-like outgrowths for attachment • Endospore • Thick wall around the chromosome during unfavorable growth conditions • Resistant • Live for decades! • Bacillus and Clostridium strains

  13. Movement • Flagella • Run and Tumble • slime • Obtaining Energy • Autotrophs • Heterotrophs

  14. Releasing Energy • Obligate anaerobes • Clostridium botulinum • Facultative anaerobes • Escherichia coli • Obligate aerobes • Clostridium tuberculin

  15. 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

  16. 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

  17. Bacteria and Disease • Pathology – study of disease • Pathogens • Damage to tissues • Release of toxins • Exotoxins (Gram+, Clostridium tetani) • Endotoxins (Gram-, Escherichia coli)

  18. 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

  19. Antibiotics • Drugs to combat bacteria only! • Complete entire course of medication • Water is essential • Check Gram +/- status • Resistance • Abuse and Misuse • Evolution • mutations

  20. Human Uses of Bacteria • Soil • Food • Industry • Biotechnology

  21. 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

  22. Viruses are notmembers of the Six-Kingdom System of Classification • Detached Fragment of a genome • Infect all taxonomic levels! • They are highly specific

  23. Characteristics • Size • Smallest biological particle • 17 nm to 1000 nm • Structure • Not cellular • Nucleic acid (DNA or RNA) • Protein coat • Shape • Helical or isometric

  24. Bacteriophage • Infect bacteria • DNA • Example: T4 phage

  25. Lytic Cycle - Virulent 1. Attachment 2. Entry 3. Replication Viral Infection

  26. 4. Assembly 5. Release  lysis!

  27. http://www.cat.cc.md.us/courses/bio141/lecguide/unit2/viruses/adlyt.htmlhttp://www.cat.cc.md.us/courses/bio141/lecguide/unit2/viruses/adlyt.html

  28. Lysogenic Cycle - temperate

  29. 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

  30. http://www.cat.cc.md.us/courses/bio141/lecguide/unit2/viruses/lysosum.htmlhttp://www.cat.cc.md.us/courses/bio141/lecguide/unit2/viruses/lysosum.html

  31. Viruses and Disease • Vaccine protection • Attenuated • Inactivated • Oncogenic viruses • Retroviruses • Prions • Stanley Prusiner • Scrapie, BSE, CJD

  32. 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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