Unit 5 Flashcards
5 phyla of Archaea
Euryarchaeota
Thaumarchaeota
Nanoarchaeota
Korarchaeota
Crenarchaeota
what is the phylogenetic tree based on?
16S r RNA
what is the evolution of Archaea driven by?
HGT between phyla
what are the common traits shared by all Archaea?
- ether linked lipids
- lack of peptidoglycan in cell walls
- structurally complex RNA polymerases
- RNA polymerase resemble eukaryotic enzymes
- extreme metabolic diversity
- chemoorganotrophic or chemolithotrophic organisms
- aerobic and anaerobic organisms
Euryarchaeota
halophilic (salt-loving obligate aerobes)
methanogens (strictest anaerobes)
hyperthermophilic
acidophilic
extremophilic and non-extremophilic
what are the 2 organisms representing halophilic archaea and their characteristics?
halococcus
haloquadratum
- usually aerobic
- anaerobic is possible
- no fermentation
halococcus
largest plasmids in nature
plasmid is 30% of total cellular DNA
haloquadratum
gas vesicles for floating in hypersaline enviro
what do organisms do in high solute enviro?
either accumulate or synthetize solutes intracellularly (compatible solutes)
function of compatible solutes?
prevent dehydration under conditions of high osmotic strength
what do certain Euryarchaeota do if they do not synthesize or accumulate organic compounds?
pump large amounts of K+ from enviro into cytoplasm
- different in K+ levels maintains pos water balance
hyperthermophilic organisms
thermococcus
thermoplasma
thermoplasma
- cell wall lacking
- small genome
- DNA in globular eukaryotic-like structures
- 55C
- pH 2
- sulfate respiration
- No sterols
- Lipoglyan cell wall
methanogens
produce methane as integral part of energy metabolism
- major source of biogenic methane in nature
Methanocaldococcus jannaschii
model methanogen
enzymes for methanogenesis
central metabolic enzymes and cell division machinery- resembles bacterial structures
transcription and translation genes resembles eurkayotic organisms
acidophilic organisms
ferroplasma
picrophilus