Bacteria (Prokaryotes)
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Transcript of Bacteria (Prokaryotes)
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