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Unformatted text preview: Ingrid Shih BIO 1306-04 14 January 2011 Bacteria and Archaea: The Proka ryotic Domains 26.1 How Did • The domains of life: o Bacteria-prokaryotes o Archaea- prokaryotes o Eukarya- eukaryotes • Members of all the domains o Conduct glycolysis o Replicate DNA conservatively o Have DNA that encodes peptides o Produce proteins using same genetic code o Plasma membranes and ribosomes • SINGLE COMMON ANCESTOR TO ALL LIFE! • Prokaryotics cells vs eukaryotic o Prokaryotes- lack cytoskeleton and divide by binary fission o DNA is a single circular molecule, not in a membrane-enclosed nucleus (eukary) o Prokaryotes have no membrane-enclosed organelles • Archea have ether-linked membrane lipid while bacteria and eukarya have ester- linked membrane lipids • Bacteria Shapes: o Helical- corkscrew o Bacilli- rod o Cocci- spheres • Archaea Shapes: o Many different shapes, rarely seen, known form DNA • Earliest prokaryote: 3.5 bya • All three domains are well adapted to present-day environments • None is “primitive” 26.2 • Prokarys are the most successful organisms on Earth in terms of number of individuals • # of prokarys > 10 8 x # known stars Ingrid Shih BIO 1306-04 14 January 2011 • They are found in every type of habitat on Earth • Keys to success o Complex cell walls (Gram Stain) o Binary fussion _ gene exchange o Motile- e.g. flagella o Quick reproduction (fastest is 10 minutes) o Metabolically diverse Anaerobic and aerobic Variety of energy and carbon sources...
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