BIOLOGICAL DIVERSITY EXAM THREE LECTURE NOTES CHAPTER 28 PROKARYOTES lecture 10 19 Bacteria Archaea Roles in Our World 1 2 sheet huge role in decomposition break down of organic matter o sewage food production o cheese o yogurt bacteria is in on us o intestines digestion o on skin fight infections diseases o pathogens o can infect any living organism diverse usage for research global element cycles o nitrogen fixation o carbon oxygen and phosphorous cycling Prokaryote Fossils figure 28 1 in text oldest prokaryote fossils found 3 8 billion years ago bya o spectrographic analysis to look for lipids various fatty substances that leave a signature behind in the fossils o look at morphology o during this time period there was NO oxygen in the atmosphere so some bacteria today thrive in anoxic environments environments without or with little oxygen low taxonomy for this group difficult to analyze o trade DNA info often within populations o complex organism in determining where DNA came from most abundant life forms on earth Morphologies morphologies were used to classify three main classifications 1 bacillus coccus 2 spirillum 3 rod shaped bacteria spherical oval bacteria spiral helical colony forming prokaryotes also called filaments o difficult to classify Carl Woese separated bacteria into two different groups bacteria archaea cell membrane structure separates the two o biochemical differences in the construction of the two plasma cell membranes plasma membrane is composed of lipids ALL have glycerol and a complex fatty acid tail difference is in the BONDS o ester bond in bacteria o ether bond in archaea stable resistant to break down archaea are extremophiles hottest and coldest places on the planet o cell wall differences bacteria cell walls have peptidoglycan increases structural stability of organisms bacteria can handle drying out well archaea have NO peptidoglycan o genetic differences associated with protein production the MODE by which protein production occurs differs dramatically archaea have same as eukaryotes o major rationale underlying idea why archaea are more closely related to eukarya bacteria have a mode that is more unique to the group o simpler system than archaea and eukarya Archaea extremophiles more likely to be found in extreme conditions in comparison to bacteria but also found elsewhere in normal conditions o temperature extremes hot or cold o salinity o low nutrient environments efficient metabolizers o chemical extremes high sulfur environments o also referred to methanogens producers of methane or atmospheric gas 10 20 groups of archaea o thermophiles 60 80 C 140 175 F found in hot places sometimes in hydrothermal vents deep in the ocean deep freshwater lakes loaded with archaea vents are loaded with hydrogen sulfide archaea gain energy by metabolizing hydrogen sulfide Thermus aquaticus cellular structures do not break down in extreme environments using other energy sources that other organisms are incapable of living off of type of archaea with a particular enzyme taq polymerase enzyme is important because it does not denature in extreme temperatures taq polymerase is used in PCR polymerase chain reaction o used to replicate DNA sequences for genetic analysis o acidophiles found in very low pHs 2 0 HCl thrive in extremely acidic places acid mine drainage natural habitats bogs pine forest soil food sources low pHs buttermilk yogurt sour cream o halophiles thrive under high salinity salty conditions o methanogens Great Salt Lake Great Sea around 40 salinity ocean water has 25 30 salinity pigments pink show up in the presence of halophiles block salt uptake maintain a neutral pH for self also in food soy sauce produce methane gas all of these are archaea no bacteria commonly found in wetland habitats swamps marshes found in garbage dumps exponentially increasing o significant source of methane sometimes they pipe the methane to power producing plants largely responsible for the atmospheric methane gas also produced by cattle burping farting 10 12 overall animal production methanogens archaea live inside of cows and humans and termites o digestive system stomach intestines o termites are responsible for 4 5 of world methane production methanogens on Mars searching soil samples for archaea DNA most basic way of characterizing domain bacteria diversity is by the structure of the cell wall o cell wall type is determined by gram staining gives insight to biological structure of cell Domain Bacteria wall gram have a thick cell wall single layered major structural component is peptidoglycan on the outside archaea have NO peptidoglycan stain added to bacterial solution stains peptidoglycan PURPLE o purple cell two layers in cell wall gram thin sheet of peptidoglycan between cell membrane and outer cell wall o mostly covered by lipid bilayer membrane similar to internal cellular membrane lipopolysaccharides porin protein lipopolysaccharides and porin used to recognize toxins food other organisms and decides whether or not to allow entry to the cell can block antibiotics o stain used to stain gram is blocked by the porin in the outer layer from staining the peptidoglycan NO purple second stain is added into the stain solution and gets through outer membrane stains the layer PINK differences btw gram and gram gram is more susceptible to antibiotics gram is more difficult to treat due to the lipid bilayer morphology is not helpful only pink and purple tell what type of cell wall structure one is dealing with Gram Bacteria phylum Actinobacteria o mostly soil bacteria also found on teeth as plaque o many Actinobacteria infect plant roots forming nodules round structures on typical root nodules are full of bacteria that fix nitrogen atmospheric nitrogen is converted into ammonia fertilizer for the plant o enhances plant growth and reproduction for plants and plant provides carbon for bacterial growth interaction symbiosis mutualism both organisms benefit o dental plaque o antibiotic production full of Actinobacteria biofilm bacteria archaea fungi and algae matrix composed of polysaccharides that come together through many Actinobacteria create toxins that will kill other groups of bacteria or fungi streptomycin tetracycline produced from Actinobacteria very energetically expensive to produce toxins for Actinobacteria protects the site where they are attached from fungi and bacteria and from competition for food o enhances growth rates and in turn increases reproduction
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