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Carl Woese
came up with the idea to use a small subunit of the ribosome to characterize organisms (mainly prokaryotes)
based on the sequence data - proposed a complete change in our understanding of the relationship between organisms
True/False: Archaea has peptidoglycan present in cell wall
false
Archaea: S-layer
most common
proteins or glycoproteins
Archaea: S-layer + external layer
the external layer is either a protein sheath or a polysaccharide
Archaea: S-layer + pseudomurein
PG-like
N-acetyltalosaminuronic (NAT) instead of NAM
beta-1,3 glycoside links between NAT and NAM
L-AA crosslinks
Pseudomurein are
resistant to lysozyme and antibiotics that target bacterial cell wall (PG)
Archaea: complex polysaccharide
single thick layer
no s-layer
Archaea: Glycocalyx
not a cell wall rather a slime layer
Archaea: Outer membrane
not a cell wall
Plasma membrane of archaea
differs slightly from both bacteria and eukarya
Archaea PM contains
hydrocarbons of repeating isoprene units
Isoprene units of archaea are attached to ___ by ____
glycerol; ether linkages
Two major types of archaeal lipids
glycerol diether and diglycerol tetraether
Glycerol diether
2 hydrocarbons attached to the glycerol
each usually 20 C in length
Diglycerol tetraether
2 glycerol linked by two hydrocarbons that are 40 C in length
True/False: Archaea has both hopanoids and sterols
False
Archaea chromosome are ___ and reside in ____
circular dsDNA; nucleoid
archaea genomes compared to bacteria are
smaller
Genetic material in archaea are associated with
histones
Histones
proteins used to condense DNA/packaging
Archaeal flagella structure
filament
motor complex
rotation
Filament
not hollow and proteins are added to the base for growth
Motor complex
proteins are in the PM
Rotation
ATP hydrolysis, directions of cells are either forward or reverse
there are no runs/tumbles
Archaea typically lives in
extreme environments (extremophiles)
Halophiles
thrive in high [salt]
Psychrophiles
0-20 celcius
Thermophiles
50-80 celcius
Hyperthermophiles
>80 celcius
Barophiles
pressure > 1 atm
Acidophiles
low pH
Methanogens
produce methane
Thermophiles proteins stability
AA composition similar to heat-labile bacteria
highly hydrophobic cores and ionic interaction on surfaced, creating a low tendency to unfold
have heat-shock proteins
Heat-shock proteins
synthesis increases with stress of excessive heat
refolds partially denatured proteins before protease recognize improper folding and destroys
DNA stability by _____ allows for the survival of thermophiles
Potassium cyclic 2,3-diphosphate (salt)
reverse DNA gyrase
proteins
Potassium cyclic 2,3-diphosphate (salt)
associates with DNA and increases stability of bases
Reverse DNA gyrase
unique form of DNA topoisomerase
introduced positive supercoils into DNA, which increases stability and prevents heat denaturation
Proteins in thermophiles
maintain the integrity of DNA
Sac7
small heat-stable DNA binding protein
binds to small grooves of DNA, increases melting point by 40 celsius
Monolayer archaea _____ tendency of heat to pull it apart
resist
Bilayer archaea are _____ stable with high temps
less, higher temps pull the two layers apart
Halophiles
have a very high salt requirement, thus inhibiting a highly saline environment
Halobacterium
the glycoprotein cell wall is high in aspartate and glutamate concentration that repels each other, thus requiring Na+ to bind to surfaces and shield negative charges
High [Na+] outside of the cell results in
water moving out of the cell causing plasmolysis
To prevent plasmolysis due to [Na+]
K+ is pumped into the cell in large amounts thus water inside and outside of the cell is maintained
Acidophiles have
the optimal environment of 0-5.5 pH, but an internal neutral pH
Sulfolobus Acidocaldrius
inhabits hot springs
allows K+to enter cells to reduce the member potential
highly impermeable PM
active H+ export by transporter
has secondary transporters, chemicals that bind and sequester H, DNA and RNA repair systems and degradation of organic acids
Impermeable PM of Sulfolobus Acidocaldrius is due to
tetraethers and calditol
Tetraethers
resist dissociations, ether links are less sensitve to acid hydrolysis
Calditol
unique to archaeal lipid head groups