Learning Obj. Lecture 9: Prokaryotes

Prokaryote diversity

• 30,000 species described

• Extreme metabolic diversity

5 Kingdoms

• Monera

• Protista

• Plantae

• Fungi

• Animali

Three domains

• Bacteria

• Archaea

• Eukarya

Significance of histones in Eukaryotes and Archaeans

Deep evolutionary connection between Archaea and Eukarya

Which domains arose first

Bacteria → Archaea → Eubacteria

Eukarya arose via endosymbiosis

Endosymbiosis

• One organism lives inside another, mutualistic relationship

• Key eukaryotic organelles originated when an ancestral cell engulfed a prokaryote

4 Archaea phylums

• Euryarchaeota

• Korarchaeota

• Crenarchaeota

• Nanoarchaeota (smallest known living cells)

Phylum Euryarchaeota

• Methanogens

  • Cow stomachs

• Halophiles

  • Photoheterotrophs

• Thermoacidophiles

  • Hot & acid environments, Thermus Aquaticus TAQ polymerase

Phylum Crenarchaeota

• Hyperthermophiles (temperatures)

• Chemolithotrophs (energy from oxidizing organic compounds)

• Chemoorganotrophs (energy from oxidizing organic compounds)

Phylum Korachaeota

• Know they exist because we’ve sequenced DNA

  • Circular w/histones

Phylum Nanoarchaeota

• Parasitic on other archaeans

Domain Bacteria/ Eubacteria (gram±)

Gram positive (violet)

• Staphylococcus & Streptococcus

• Thick peptidoglycan

• Single plasma-membrane

Gram negative (red)

• Cyanobacteria & Spriochaetes

• Thin middle layer peptidoglycan

• Double plasma membrane around

Domain Bacteria (genera)

• Proteobacteria (endoparasitic of eukaryotic cells)

• Spirochetes

  • Tepanema (syphilis)

  • Borrelia (lyme disease)

Biogeochemical Cycles (Nitrogen-Cycle)

N2 → Nitrogen-fixing bacteria → NH3 → Nitrifying bacteria → NO3- → Denitrifying bacteria → N2

Organisms in N2 cycle

• N2 fixing [Nostoc, anabaena], Rhizobium

• Nitrifying: Nitrosoponas, nitro bacter

• Denitrifying: Pseudomonas

• Decomposers/Ammonification: Pseudomonas, Bacilius (gangrene)