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