Archaea Flashcards
What are Archaea
Prokaryotes which can represent one domain
They usually live in extreme condition
What are the 2 major phyla in Archaea
Euryarcheota
Crenarchaeote
What is in the cell structure of Archaea
S-layer, Cell-wall, Archaellum, Canulae, Hooks, Cytoplasmic membrane
What does the S-layer do
Has a role in cell shape
What are properties of the Archaea cell wall
Made of Pseudomurein and isnt always present
Heteropolymer which is similar to bacterial peptidoglycan
What Are Archaea cell walls resistant to
Lysozyme
Most antibiotic targeting bacterial Peptidoglycan Synthesis (penicillin)
What is the Archaellum
Used for motility and powered by ATP
What are canulae
Extensions of the cell
What are hooks
Allows cells to stick together
What are the properties of the Archaea cytoplasmic membrane
Phospholipids contain no fatty acids but instead isoprene’s
Phospholipids ether - not ester linked
More stable than bacterial membranes
Present as monolayers or bilayers
What is the organisation of chromosomes in Archaea
Circular chromosomes and plasmids
Histones
How are genes organised in Archae
Operons
Do Archaea have introns
Yes
How many RNA polymerases in Archaea
1 which is similar to RNAP2 in eukaryotes
How is protein synthesis done in Archaea
Translation and transcription are coupled
Involves several translation factors like in eukaryotes
Ribosomes are 70S particles
Where are Archaea found
Can be found in lots of places (very diverse) - extremophiles
What is a hyperthermophile example
Acidianus infernus (Crenarchaeota) - Isolated in geothermic hot spring; optimal growth at 75°C/pH 2.5-3 Grows anaerobically (produces H2S) or aerobically(produces H2SO4
Thermococcus barossii - Isolated from a hydrothermal vent; optimal growth at 82°C/pH 2.5-3 Grows anaerobically, requires Sulfur
What are the features of hyperthermophiles
High growth temperature (80 to 120°C)
Most require elemental sulfur for growth
Often acidophiles (pH 1 to 3)
What are examples of halophiles
Halobacterium halobium - Prevalent species in Great Salt Lake; optimal growth at 75°C/pH 2.5-3
Uses light as energy source to secrete H+; gradient used to produce ATP Other transporters (halorhodospin) ensure ion transport
What are the features of halophiles
Mostly Euryarchaeota (few bacteria & eukaryotes)
found in evaporating ponds, Dead sea, Great Salt Lake
Require up to 5M NaCl for growth (0.6M in seawater!)
What are methanogens
Euryarchaeota
Found in anaerobic environments (rumen, gut, marine sediments…)
Use acetate/formiate/CO2 as electron acceptor
Ex: CO2 + 4H2 → CH4 + H20
What are examples of Methanogens
Methanopyrus kandleri -Isolated in deep ocean on hydrothermal vent Optimal growth at 105-115°C
Methanobrevibacter smithii - Prevalent species in the human gut Contributes to removal of bacterial end products of fermentation
Where can Pseudomurein be found
Exclusively in Arcgaea
Extremosus infernus is an organism using light for energy source, hydrogen sulfide as an electron donor and carbohydrates as a carbon source. This bacterium is:
photolithoheterotroph
