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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 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 • Unusual lipids in their cell membrane • DNA similar to eukaryotes • No peptidoglycan in their cell wall
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
Kingdom Eubacteria • Shapes • Bacilli • Straight rod • Cocci • spherical • Spiral • Long and spiral • Groupings • Staph- graph cluster • Strep - chain
Gram Staining Bacteria Steps: 1. crystal violet 2. iodine stain 3. alcohol wash 4. safranin Positive = purple Negative = pink
Gram Positive Bacteria Gram Negative Bacteria Mixed Bacteria
What Gram Indicates • Difference in the cell wall (peptidoglycan) • Why Gram Stain? • Determines antibiotic efficiency • Indicates different toxins • React to disinfectants differently
The Biology of Eubacteria • Cell Wall • Peptidoglycan • protection • Cell membrane and Cytoplasm • Lipids and enzymes • surface area • ribosome
Pili • Hair-like outgrowths for attachment • Endospore • Thick wall around the chromosome during unfavorable growth conditions • Resistant • Live for decades! • Bacillus and Clostridium strains
Movement • Flagella • Run and Tumble • slime • Obtaining Energy • Autotrophs • Heterotrophs
Releasing Energy • Obligate anaerobes • Clostridium botulinum • Facultative anaerobes • Escherichia coli • Obligate aerobes • Clostridium tuberculin
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
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
Bacteria and Disease • Pathology – study of disease • Pathogens • Damage to tissues • Release of toxins • Exotoxins (Gram+, Clostridium tetani) • Endotoxins (Gram-, Escherichia coli)
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
Antibiotics • Drugs to combat bacteria only! • Complete entire course of medication • Water is essential • Check Gram +/- status • Resistance • Abuse and Misuse • Evolution • mutations
Human Uses of Bacteria • Soil • Food • Industry • Biotechnology
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
Viruses are notmembers of the Six-Kingdom System of Classification • Detached Fragment of a genome • Infect all taxonomic levels! • They are highly specific
Characteristics • Size • Smallest biological particle • 17 nm to 1000 nm • Structure • Not cellular • Nucleic acid (DNA or RNA) • Protein coat • Shape • Helical or isometric
Bacteriophage • Infect bacteria • DNA • Example: T4 phage
Lytic Cycle - Virulent 1. Attachment 2. Entry 3. Replication Viral Infection
4. Assembly 5. Release lysis!
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
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
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
Viruses and Disease • Vaccine protection • Attenuated • Inactivated • Oncogenic viruses • Retroviruses • Prions • Stanley Prusiner • Scrapie, BSE, CJD
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