 One out of the two kingdoms of bacteria › Unicellular prokaryotes › Ancestors of eukaryotic cells  Emerged over 3.5 billion years ago  First discovered in 1977  Represented today by a few groups of bacteria inhabiting extreme environments

 Archaebacteria are quite different from eukaryotes › They don’t possess membrane-bound organelles › They have a thick cytoplasm › Lack Peptidoglycan › They produce protein from their DNA › Their genes have introns › Have unique lipids in plasma membranes

 Asexual Reproduction › Binary Fission  Genetic material can be exchanged between cells by three different proccesses › Transformation › Transduction › Conjugation

 1/10 th of a micrometer- 15 micro meters  Can withstand pressures of above 200 atmospheres  Non-pathogenic › They can live in and around other organisms but not infecting them

 Make up the largest group of Archaebacteria known of so far  Usually coccoid (spherical) or bacilli (rod shaped)  Strictly anaerobic › Poisoned and killed by traces of oxygen

 Convert CO 2 into Methane › Release 2 trillion kg of methane gas per year  The large quantities of methane influence carbon dioxide levels in the atmosphere

 Evolved before there was oxygen in the atmosphere › Developed new ways of producing energy without oxygen present  Instead of photosynthesis, they combine Hydrogen, (H 2 ), with Carbon Monoxide, (CO 2 ), to form Methane, (CH 4 )

 Could have lived anywhere in ancient times  Today, they live only where no oxygen is present and hydrogen and carbon dioxide are available › Sewage treatment plants, stagnant water, hot springs, and bottom of the ocean  Common in wetlands › Responsible for marsh gas, CH 4  Found in intestinal tracts of ruminant and humans › Responsible for belching and flatulence

 Lives best in relatively high temperatures › o C, o F  Found in geothermal heated regions of the Earth › Yellowstone National Park, deep sea hydrothermal vents, and decaying plant matter

 Obligate Thermophiles (Extreme Thermophiles) › Require high temperatures for growth, o C  Facultative Thermophiles (Moderate Thermophiles) › Thrive at high and low temperatures, o C  Hyperthermophiles › Optimal temperatures are 80 o -105 o C

 Anaerobic  Live in extreme environments › Thrive in acidic, rich in sulfur, and high temperature areas › Can tolerate temperatures up to o C › Acid levels- pH 2 to 3  The plasma membrane contains high amounts of saturated fats  Its enzymes are able to withstand extreme conditions without denaturation › a structural change in macromolecules caused by extreme conditions

 Halophile means “salt loving”  Aerobic microorganisms › Create ATP by aerobic pathways  Most can perform a special type of photosynthesis without chlorophyll › Can also use the high concentrations of salt to help produce energy

 Can live in high concentrates of salt › 10 times the amount of salt content of normal ocean water › Great Salt Lake, Utah, Owens Lake, Calf.  Optimal growth occurs at 20-25% salt solution › Can continue to grow in solutions up to 37%  Use osmotic pressure and chemical substances to control the amount of salt inside the cell

 Coated with a special protein covering › Used to allow only certain levels of salt into the cell.  This covering helps to seal in water with the right level of salt  Uses diffusion to help keep the salt content at the right level

 Halophiles have turned the land surrounding the Great Salt Lake a reddish color › This happens after flood water spreads onto the land

 Tinted red by salt-loving bacteria  15-30% salinity

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