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Bacteria (Prokaryotes) Chapter 27 What you need to know! • Different Domains and Kingdoms of prokaryotes • How chloroplasts and mitochondria evolved through endosymbiosis Domains and Kingdoms • Bacteria Eubacteria • Archaea Archaeabacteria Characteristics of Both • • • • • • • Prokaryotes Evolved all metabolic pathways on earth No membrane bound organelles Smaller ribosomes Haploid (no meiosis) Can have plasmids Can have flagella (made of flagellin not tubulin) • Classified based on: metabolism then shape then staining – Autotrophs: photosynthetic and chemosynthetic – Heterotrophs: parasites, saprobes (decomposers), and photoheterotrophs (use photosynthesis and consume food) Archaeabacteria • Methanogens: anaerobic, heterotrophic, produce methane, found in: mud, swamps, guts of cows, and termites • Extreme Halophiles: aerobic, heterotrophic, or anaerobic, photosyntheitc (with pigments), live in high salinity (Salt Lake, Dead Sea) • Thermoacidophiles: chemosynthesis, autotrophs, live in high heat (150 – 180 degrees F) and acidic environments (pH 2), hot springs, sulphur vents Eubacteria • Endospores: DNA packed into cell wall for long term hybernation/survival • Identified by shape: cocci (sphere), bacilli (rod), spirilla (spirals) • Distinguished by staining method • Cyanobacteria (formerly blue/green algae): photosynthetic, some fix nitrogen • Chemosynthetic bacteria: autotrophs, some fix nitrogen • Nitrogen Fixing Bacteria: heterotrophs, mutualistic with plants, live in modules • Spirochetes: spirilla, move in a corkscrew motion Endosymbiotic Theory States that mitochondria (M) & chloroplasts (C) were prokaryotic organisms that were swallowed by another larger prokaryote 3-4 byo through a process called endocytosis. M & C were not digested but formed a: mutualistic symbiosis with their host. Endosymbiotic Theory Arguments that support ET 1. M, C, and N have their own DNA 2. M and C DNA is similar to prokaryotic DNA 3. M and C multiply independent from nucleus/mitosis 4. M, C, and the Nucleus have double membranes Oxygen? Yes or No • Obligate aerobes: need oxygen environment to live • Obligate anaerobes: need an oxygen free environment to live (absolutely no oxygen) • Facultative anaerobes: can survive w/ or w/out oxygen