Chapter 5: The Archaea
Thermophilic Archaea (4)
- Found in hot springs, geysirs, hydrothermal vents - Grow at temperatures between 85o C and 122oC - Example: Old Faithful and Thermal Pool Yellowstone - under water 'chimneys' are formed when Hot 350C sulfide rich gasses meet 4C ocean water
why are archaea sometimes called "extremophiles" ?
- Many are found in extreme environments (low pH, high temperature, high salt concentration, high acidity)
Halophilic Archaea: (2)
- Survive under very high salt concentrations (25%) - Example: Dead Sea & Salt Pans, San Francisco
Arman Group: (5)
- found in acid mine drainage, acid bogs where pH < 1.5 - Cell sizes are 0.1 um - free living or found in association - never been cultured - Their genome has been sequenced
Methanogenic Archaea: (3)
- produce methane - anaerobic environment - Examples: marshes, land fills, septic systems
what are 3 major differences archaea has from bacteria under the microscope?
1. cell wall composition is different- archaea do not contain murein (peptidoglycan) 2. membranes contain lipid ethers (fatty acids) 3. exhibit very different metabolic properties
arachaea are similar to eukaryotes in the fact that they both:
1. do not have peptidoglycan 2. have histones
The three major physiological groups of the Archaea are:
1. extreme thermophiles - live at extremely high temperatures 2. extreme halophiles - require high concentrations of salt 3. methanogens - anaerobes, produce methane from CO2 and H2
Anaerobic Sulfur Reduction Widespread:
Unusual organisms found at the hydrothermal vents
archaea are similar to _______.
bacteria - they both have the same rods and cocci shape/structure
Extreme thermophiles are organisms that _____.
grow at high temperatures
Halophiles are organisms that ____________.
grow in high salt concentrations
The Archaea consist of three groups, the thermophiles, methanogens and _________.
halophiles
where is archaea commonly found?
in nature (dominant in the ocean)
An example of an environment where you are likely to find methanogens: _____.
landfills
archaea is not ________ to animals and humans.
pathogenic
Phylogeny of the Archaea does not always reflect______.
physiological similarities
archaea is a major group of ______.
prokaryotes
