Module 3: Archaea Flashcards
Euryarchaeota
contains the methanogens
Crenarchaeota
extremophiles
high temperature, high acidity (acidophiles), high salinity, or high pressure (barophiles)
modified proteins that contain more alpha helices
use of amino acids that encourage salt bridges and, specifically, side chain interactions
Thaumarchaeota
most abundant organism on earth
low temperature
oxidize ammonia
Nanoarchaeota
Nanoarchaeum equitans
is a symbiont that associates with Ignicoccus
How are amino acids different between mesophiles and extremophiles
increased proportions of arginines and tyrosines
fewer cysteines and serines
How were archaea first discovered and by whom
Carl Woese & George Fox in 1970’s
distinct rRNA sequences
Karl Stetter discovered Ignicoccus and Nanoarhcaeota, thinking they were bacteria
key differences and similarities between archaea and bacteria
differences:
no methane producing bacteria
RNA polymerase
no nucleosome
same size: approx. 0.5-5 microns shapes: coccus, rod-like, spiral mRNA, tRNA, ribosomes and DNA inclusion bodies: gas vessicles single circular chromosome absent of a membrane-bound nucleus
Key differences and similarities between archaea and eukaryotes
same:
RNA polymerase
histone proteins
package DNA in a nucleosome
Differences in histones of archaea and eukaryotes
Eukarya: histone octamer interacts with approxiamtely 160bp of DNA
Archaea: histone tetramer interacts with approximately 60bp of DNA
What group of archaea are associated with methanogenesis
methanothermobacter
methanosarcina
methanocaldococcus
methanococcus
major phyla of the archaea and describe their common characteristics
crenarchaeota - extremophiles euyarchaeota - methanogens korarchaeota - uncultured archaea nanoarchaeota - only nanoarchaeum which is symbiont with ignicoccus thaumarchaeota - oxidize ammonia
describe the shapes of cells found within the archaea
Typically 0.5-5 microns in diameter
Coccus, rod-like, spiral, pleiomorphic
explain how Haloquadratum walsbyi tolerates high salinity
square-shaped
very high surface:volume ratio
increased biphytanyl in plasma membrane
list three types of methanogens based on their growth substrate
hydrogenoclastic - break down hydrogen
Acetoclastic - break down acetate
Methylotrophic - break down one carbon compounds
explain where you would find methanogens and why
anoxic environments - landfills, large intestines, sediments, waste water sludge, rice paddies, hydrothermal vents, cecum, rumen, termites
inhibited by oxygen
require carbon dioxide and hydrogen - end products of fermentation
describe why the relationship between Nanoarchaeum and Ignicoccus is “bizarre.”
Ignicoccus:
ATP production in the periplasm
Nanoarchaeum:
does not contain any metabolic genes - including not being able to make its own membrane (lipid production), ATP production, amino acid production, nucleotide production
IS able to produce an S-layer, which protects Ignicoccus too
Cytoplasmic membrane of archaea compared to bacteria
Head group:
A - glycerol 1-phosphate
B - glycerol 3-phosphate
Tails:
A - phytanyl chains
B - fatty acid hydrophobic
Attachment:
A - Ether group
B - Ester group
Cell Wall differences
B:
beta 1-4, glycosidic linkages
NAMs
Presence of D-isomer amino acids
A:
beta 1-3, glycosidic linkages
NATs - not susceptible to lysozymes
No D-amino acids in the cell wall, only L-isomers
Flagella of Archaea compared to Bacteria
B:
hollow tube
flagellin subunits pass through to grow through the tip
single flagellin protein
A:
solid
builds from base, like hair
multiple flagellin protein types
