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Archaea
Shauna Menzella
 Domain Archaea wasn’t recognized as a major domain until the
20th century
 Although many books and articles refer to them as
“Archaebacteria” the term has since been abandoned
 They aren’t bacteria at all- they’re Archaea
Overview
 Similar to bacteria in size and simplicity
 Radically different in molecular organization
What is
Archaea?
 Intermediate between bacteria and eukaryotes
 Unicellular
 Inhabiting extreme conditions
 Prokaryotes
Structure
 No nucleus
 Do not possess packaging proteins
 Possess proteins similar to histones
Structure
(continued)
 Single cellular chromosome
 Two nucleotides
 One type of RNA polymerase
 Wide variety of shapes (flat, square, etc.)
 Some have flagella
Three Types of
Archaea
 Crenarchaeota
 Characterized by their ability to
tolerate extreme temperatures
in acidity
Three Types of
Archaea
(continued)
 Euryarchaeota
 Includes methaneproducers and salt-lovers
Three Types of
Archaea
(continued)
 Korarchaeota
 Diverse and widely
encompassing group of
which little is known
 Asexual
Reproduction
 Binary or multiple fission
 Fragmentation
 Budding
 Cell division is controlled in a cell cycle
 If a species of Archaea exists in more than one form, they will all
have the same genetic material
 Extremophiles
 Live in extreme environments and temperatures
 Some love the heat, often above 100 degrees C
 Geysers at Yellowstone National Park
 Some love the cold
 Polar seas
Ecology
 Some love salt (halophiles)
 Hyper-saline environments