Topic 3 Flashcards
Where do archaea live?
Live in most inhabitable places on earth, very extreme locations
Are there achaeal human pathogens?
NO, have never been proven to be the causation of disease
Are archaea extremophiles?
YES
Phylogenetic trees are established by what
Comparison of rRNA genes, Woese and fox began these studies
What were the first archaea discovered
Methanogens, all methane poducing things are methanogens
What is the size of Archaea
0.5-5um, but vary greatly
What is the shape of archaea
ROds, cocci, spirals, irregular shapes, rectangular, squares (halobacterium, flat squares so large surface area, so high nutrient intake, found in water capturing sunlight into atp)
What is in the cytoplasm of archaea
Similar to bacteria
-inclusion bodies observed (gas vacoules)
-single, circular chromosome
-DNA replication enzymes look like those of eukarya
-histones present (early branching point of eukarya and archaea fom bacteria
-histones form structures that wrap around DNA, different from eukarya though
How are histones wrapped around dna
tetramer of positively charged histones used for dna to wrap around rather than octomer like eukarya
What is an actin homolog found in this
Ta0583, found in thermoplasma acidophilum , resembles actin from eukarya
Cell Envelope consists of?
Cell wall, plasma membrane, and NO OUTER MEMBRANE
Plasma membrane consists of?
-G1P, instead of G3P in euk and bac
-Ether linkages, instead of ester linkages in bac: ether provide more stability
-phytanyl side chains (repeating isoprene units) instead of fatty acid chain
Monolayer of plasma membrane?
Phosphoglycerol head on both ends, since they are covalently linked in middle, creates by-phytanyl chains
-STABILITY so allows fo them to live in high temp environments
THIS AND ETHER LINKAGES ALLOW FOR STABILITY
What increases stability in plasma membrane
Ether linkages and biphyntanyl chains (two chains covalently link togethe to form to heads on both ends (think fatty acid but tails bonded together but for ARCHAEA so phytanyls are bonded together
-ring pentane structues are also added to tails for stability (isoprene of phyntanyl)
Ignicoccus is an exception for what?
-has outer membrane and periplasm similar to gram negative bacteria
-atp synthase enzymes are house in OUTER MEMBRANE
VERY UNUSUAL EVEN FOR ACHAEA
-This is why ignococcus is an exception for having an outer membrane that also has atp synthase enzymes on it. needs it bc nano need it, there are also lots of vesicles in the periplasm of ignococcus, it carries lipids, proteins, whatever that go to nanoarachaeum
What is the cell wall made up of
-Composed of pseudomurein, similar to bacteria peptidoglycan (pseudopeptidoglycan)
-NAM (n-acetylglucosamine AND NAT (n-acetylosaminuronic acid)
-Beta 1,3 linkages of nag and nat
-LYSOZYME insensitive
-has L amino acid 4 peptide chain instead of D amino acid
Cell Surface
1) S layer: protect against predation/ virsues and mediate adhesion
2) cannulae: hollow glycoprotein tubes that link cells together to form a complex network, use this to exchange stuff
Archaellum
-used to move
-grows from the base rather than the tip (like hair)
-Uses ATP not Proton motor force to spin
not evolutionary related to flagellum
Four major phyla
1) Euryarchaeota
2)Crenarchaeota
3)Thaumarchaetoa
4) Nanoarchaetoa
Info about crenaechaeota
-Extreme lovers, high temp, high pressure, high acid
-thermophiles or hyperthermophiles
-Acidophiles (thrive in low pH) acid mine drains
-Barophiles (thrive in high pressure) bottom of ocean
What are adaptations of crenarchaeota
Membrane:
-tetraether lipids/ lipid monolayer
PACK biphyntanyl layer as this keeps membrane stable and intact
Proteins:
MODIFIED PROTEINS
-more alpha helical regions, more hydrogen bonding so more tighter and stabilized
-more salt bridges and side chain interactions (pos and neg charges make it stronger)
-more arginine/tyrosine (have side chains that promote side and salt bridges)
-less cysteine/serine
STRONG CHAPERONE PROTEINS
-help keep proteins folded, ensure they dont unfold at high temps
Dna:
THERMOSTABLE DNA BINDING PROTEINS
keep dna stabke and not denatured like chaperone proteins
REVERSE DNA GYRASE ENZYME
type of topoisomerase that supercoils DNA to ensure it stays together at high temps
Euryarchaeota
Halophiles! - salt lovers
ex: halobacterium
-require 1.5 molar salt to grow
-live in high salt environments with 5-35% salinity (ocean is usually 3.5 salinity) so it needs ALOT
What are hypotonic, hypertonic and isotonic solution and their affect on cells
Hypotonic solution (low salt solution) net movement into cell
Hypertonic solution (high salt solution (net movement out of cell
Isotonic (equivalent salt solution) no net loss or gain
How do halophiles deal with osmotic shock and loss of water?
-They create an isotonic like solution
-Have VERY HIGH INTRACELLULAR [K+] to offset high extracellular [Na+]
-Causes the ions to be balanced, so no h2o net loss or gain
-these cells pump in potassium from environment to make osmotic pressure the same,
-K+ not toxic to proteins and dna in cell like Na, it is a compatible solute