When were archaea discovered?
1970s with RNA sequence data
What’s the most importatnt difference between Bacteria and Archaea?
Bacteria have peptidoglycan in cell wall, but Archaea don’t
Prokaryotic cell structure
- unicellular
- no nucleus or membrane bound organelles
Bacterial cell wall
- G+ has thick peptidoglycan
- G- has thin peptidoglycan and outer lipopolysacchride membrane
Bacterial flagella
- different from other flagella
- circular motor spins
Spirochetes
- Have internal flagellum (axial filament) that runs between cytoplamic and outer membrane
- mostly free living and anaerobic
- some are pathogens (syphilis and lymes)
- chemoheterotrophic
Chlamydias
- live only as intracellular parasites
- aerobic
- G- cocci
- one of the smallest prokaryotes
- small genome : 1-1.3 megabases
- Elementary Bodies are infective and Reticulate bodies replicate in cells
- very little peptidoglycan –> don’t stain, but are still sensitive to penecilin
Hyperthermophilic Bacteria and Hadobacteria
- G- and sometimes high GC content
- not monophyletic
- best above 80C some can survive above 122C
- Aquifex = chemoautotrophs living in volcanic vents and hot springs (similar to archaea)
- Deinococcus = resistant to radiation –> used in bioremediation of toxic waste sites
- Thermus aquaticus = sourse of DNA polymerase used in thermocyclers (TAQ)
Actinobacteria
- Filamentous (fungi like)
- Not all have high GC content
- Streptomyces are sources of antibiotics
- Myobacterium tuberculosis and M. Leprae
- Typically G+ and non spore forming
- some have mycolic acid
- important decomposers in soil
- mostly aerobic
Firmicutes
-Includes Bacilli (aerobic) and Clostridium (not)
-Gram positive
Staphylococcus and Streptococcus
-Heliobacteria = anaerobic, photoheterotrophic N-fixers
-Mycoplasmas = tiny obligate parasite with no cell wall because it can’t make peptidoglycan –> steals sterols from host for membrane
Cyanobacteria
- Most diverse and ecologically successful group of bacteria
- exists in all terrestrial and aquatic habitats
- big, multi-shaped, G+
- Blue bc of pigments (phycocyanin)
- uses chloryphyll a
- some fix nitrogen
- ancestor of chloroplast
Proteobacteria
- Gram negative
- Super diverse (like proteus)
- N-fixing soil bacteria
- usually anaerobic
- alpha proteobacteria = mitochondria origin
- ancestor was probably photoautotrophic
- tons of human pathogens
Photoautotrophic purple bacteria + relatives are anoxygenic and anaerobic and they use bacteriochlorophyllls instead of chlorophyll a
Other bacteria phylum
bacteriodetes synergistetes chrysiogenetes thermodesulfobacteria fusobacteria acidobacteria deferribacters thermotogae nitrospirae chloroflexi dictyglomi
When/who discovered archaea
1970s Carl Woese
Do archaea form spores?
no
Lipid of archeae
L-glycerol phospholipids in backbone
ether-linked and branched isoprenoid side chains
stabler than bacteria
What forms of eating can archaea do?
- photoheterotroph, chemoheterotroph, and chemoautotroph
- NOT PHOTOAUTOTROPH
Describe archaea flagella.
Is it similar to the bacterial?
- not homologous
- thinner, solid, and powered by ATPase
T/F all archaea are extremophiles
-false… they can be found in all habitats
Many archaea are infected by host specific viruses. What does this imply about evolution?
-The emergence of certain virus groups preceeded the split of archaea from bacteria
Are archaea the only ones who can perform methanogenesis?
yes
Four superphyla of archaea
- euryarchaeota
- TACK
- DPANN
- Asgard
What were the original two superphyla of archaea
-euryarchaeota and Crenarchaeota
Euryarchaeota
- Methanogens, halophiles, and thermophiles
- some halophiles can use light energy to synthesize ATP
- Halobacterium salinarium
