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