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Prokaryotes: Bacteria & ArchaeaWhy study these organisms?Prokaryotic shapesWhat do I think you should take away from our discussion of prokaryotes?Dr. Carl Woese: utilized rRNA sequencesBacterial RibosomeWoese developed a taxonomy based on the genes for a component (16s rRNA) of the small subunit of the 30s rRNA subunit of the bacterial ribosome16s rRNAA word about rRNA….Human vs. E. coli 5S rRNAWoese C, Kandler O, Wheelis M (1990). "Towards a natural system of organisms: proposal for the domains Archaea, Bacteria, and Eucarya.". Proc Natl Acad Sci USA 87 (12): 4576–9.Fig 27.15PowerPoint PresentationWhere do we find bacteria & archaea?Volcanic hot springsArchaeal Richmond Mine acidophilic nanoorganisms (ARMAN)Slide 17Table 27.2Fig 7.1Slide 20BioluminescenceProkaryotic Features:Fig 7.3Prokaryotic GenomeGenome size & metabolic capabilitiesSlide 26PlasmidsFig 27.8: PlasmidsFig 20.4: Lateral Gene TransferEvidence for Lateral Gene Transfer between speciesThermotoga maritimaAlso….Slide 33Fig 27.12Bacterial ConjugationWhat we are doing:Summary:Photosynthesis = ETCOther Prokaryotic CharacteristicsSlide 39Protein FtsZSlide 41Fig 27.6: Bacterial FlagellumIncreased membrane surface areaTable 5.1c: CellulosePeptidoglycan: Bacterial Cell WallsFig 28.14Slide 47Slide 48Things to know to this point…Prokaryotes:Bacteria & ArchaeaChapter 27Why study these organisms?Why study these organisms?•Biomass & number of species!•Disease•Gene cloning •Bioremediation•Global change–Oxygen–Nitrogen cycle & pollution•Model organisms for research•ExtremophilesProkaryotic shapesWhat do I think you should take away from our discussion of prokaryotes?•Tremendous diversity that allows prokaryotes to inhabit virtually all environments•Thus they posses great variations in genes and gene products that provide life essential functions in these environmentsDr. Carl Woese: Dr. Carl Woese: utilized rRNA sequencesutilized rRNA sequencesBacterialBacterial Ribosome RibosomeWoese developed a taxonomy based on the genes for a component (16s rRNA) of the small subunit of the 30s rRNA subunit of the bacterial ribosome16s rRNAhttp://www.nd.edu/~aseriann/rna.htmlA word about rRNA….A word about rRNA….http://www.biochem.uwo.ca/meds/medna/rRNA.htmlHuman vs. Human vs. E. coliE. coli 5S rRNA 5S rRNAhttp://www.biochemj.org/bj/371/0641/3710641.pdfWoese C, Kandler O, Wheelis M (1990). "Towards a natural system of organisms: proposal for the domains Archaea, Bacteria, and Eucarya.". Proc Natl Acad Sci USA 87 (12): 4576–9.Fig 27.15You are hereWhere do we find Where do we find bacteria & archaea?bacteria & archaea?Volcanic hot springsArchaeal Richmond Mine acidophilic nanoorganisms (ARMAN)Table 27.2Table 27.2Fig 7.1Draw the picture and tell the storyBioluminescenceProkaryotic Features:•Supercoiled DNA–One or more circular chromosomes–Few associated proteins–Nucleoid region (vs. nucleus)FigFig 7.3 7.3Prokaryotic GenomeProkaryotic Genome•Size of genome proportional to metabolic capabilities•Tremendous diversity of genes•Redundancy is common•Multiple chromosomes•Many small, extra-chromosomal DNAs called plasmidsGenome size & metabolic capabilitiesGenome size & metabolic capabilities•Mycoplasma - parasite that causes pneumonia–Acquires most nutrients from the host–Few enzymes, ergo few genes!•E. coli & Psuedomonas–Inhabits soils and humans!–Synthesizes almost all organic moleculesProkaryotic GenomeProkaryotic Genome•Size of genome proportional to metabolic capabilities•Tremendous diversity of genes–Many are unique to a species•Redundancy within a genome is common•Multiple chromosomes are not uncommon•Many small, extra-chromosomal DNAs called plasmidsPlasmids•Small number of genes•Copied independently of chromosomal DNA•May or may not be necessary for growth•Site of antibiotic resistance•Allows for lateral transfer of genes–Even among different species!Fig 27.8: PlasmidsFig 20.4: Lateral Gene TransferEvidence for Lateral Gene Transfer between species1. Stretches of DNA are more similar to those in genes of distantly related species than those more closely related.2. The proportion of G-C base pairs to A-T base pairs in a gene is remarkably different from the base composition in the rest of the DNAThermotoga maritima•Same habitats - deep sea hydrothermal vents •25% of genome of this bacterium is closely related to genomes found in resident archaea•Occur in distinctive clusters in DNAAlso….•Evidence for prokaryotic parasites picking up genes from eukaryotic hosts!– Intracellular parasitic bacterium Chlamydia trachomatis–Contains ~ 35 eukaryotic genes–Mechanism? ?????Fig 27.12Bacterial ConjugationWhat we are doing:•Table 27.2 - Differences among organisms of the three Kingdoms•Bacteria and Archaea:–Why we study them–Structure–Genetic diversity, how it is generated, and what are the consequences•See especially lateral gene transferSummary:•Characterized Prokaryotes & Eukarotes & Archaea (Table 27.2)–Note: mechanisms of generating diversity in prokaryotes •Moving into Prokaryotic Diversity–Morphological–MetabolicPhotosynthesis = ETCPhotosynthesis = ETCOther Prokaryotic Characteristics•Lack of compartmentalization or Organelles•Little cytoskeleton–Recent discovery of any cytoskeletal elements–Protein FtsZProtein FtsZhttp://www.umass.edu/microbio/chime/pipe/ftsz/present/ftszinvivo.htmMcIntosh, J. R. et al. J Cell Sci 2010;123:3425-3434Organization and function of FstZ filaments in eubacteriaFig 27.6: Bacterial FlagellumIncreased membrane surface areaTable 5.1c: CellulosePeptidoglycan: Bacterial Cell WallsPeptidoglycan: Bacterial Cell WallsFig 28.14Fig 28.14Things to know to this point…•Table - differences among 3 major groups of organisms•Mechanisms for generating genetic diversity in Archaea and Prokaryotes•Types and structures of carbohydrates in extracellular cell walls•rRNA & FtsZ(I am pulling this stuff right out of your


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UMD BSCI 207 - Prokaryotes: Bacteria & Archaea

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