Chapter 28 and 38

Chapter 28 and 38 - Chapter 28 Bacteria and Archaea...

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Chapter 28: Bacteria and Archaea Bacteria Archaea Microbes Medical importance Koch’s postulates Have a unique compound called peptidoglycan in their cell walls Have unique phospholipids in their plasma membranes, the hydrocarbon tails of the phospholipids contain isoprene Antibiotics that poison bacterial ribosomes do not affect the ribosomes of Archaea our eukaryotes. Microscopic organisms are bacteria or Achaea, virtually all are unnamed and un- described In terms of the total volume of living material on our planet, bacteria and Archaea are dominant life forms. Bacteria and Archaea are found almost everywhere. There are far more prokaryotes than eukaryotes, but we know so much more about eukaryotes Microbiology- the study of organisms that can be seen only with the aid of a microscope, full of exploration and discovery A tiny fraction can disrupt normal body functions enough to cause illness, are pathogenic. They have been responsible for some of the most devastating epidemics in human history 1. the microbe must be present in individuals suffering from the disease and absent from healthy individuals 2. the organism must be isolated and grown in a pure culture away from the host organism 3. if organisms from the pure culture are injected into a healthy experimental animal, the disease symptoms should appear 4. the organism should be isolated from the diseased experimental animal, again grown in a pure culture, and demonstrated by its size, shape, and color to be the same as the original organism. Used to confirm a causative link between new diseases and a suspected infectious Bacteria Archaea Eukarya Organelles? Some in limited number of species None described to date Yes. Cell wall material Almost all include peptidoglycan which contains muramic acid Varies, but no peptidoglycan and no muramic acid if present, usually made of cellulose or chitin Info processing: dna synthesis, txn, tln machinery One simple RNA polymerase, tln begins with formylmethionine ; translation poisoned by several antibiotics that do not affect Archaea or eukaryotes Dna polymerase is eukaryotic-like; one relatively complex RNA polymerase; eukaryote- like basal txn complex; tln begins with methionine Several relatively complex RNA polymerases; translation begins with methionine
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What makes some cells pathogenic? Role in bioremediation Extremophiles Why? Enrichment culture Thermophiles Using direct sequencing four categories Evaluating molecular phylogenies agent Koch’s experimental results also became the basis for the germ theory of disease, which laid the foundation for modern medicine. It’s greatest impact was sanitation initially, efforts to prevent transmission of pathogenic bacteria Virulence- the ability to cause disease. Is a heritable trait
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Chapter 28 and 38 - Chapter 28 Bacteria and Archaea...

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