The Archaea are a group of unicellular
prokaryotic (they have no cell nuclei)
organisms, separated by their biochemistry and
structure of cellular organelles from the rest of
Some taxonomists regard them as a kingdom, a
sub-kingdom, or something even larger than a
kingdom. Most are anaerobic and are
killed by oxygen. They are well-known for
living in extreme environments,including hot
springs, supersaturated salt solutions,and inside
the guts of some animals (including humans).
Their methods of getting food are as varied as
more normal bacteria, but include
Archaea are like bacteria - they are single
cells that don't have a nucleus - but they
have enough differences from bacteria to be
classified all by themselves.
They do things pretty much like
bacteria in general - they transport food
molecules into themselves through protein pumps or
channels in their outer membranes. A lot of them
live in really extreme environments, where
nothing else can live.
I'm writing a paper now about
one type of archaea that can live in boiling
water. They are unusual because they
assemble a network of tiny tubes outside of
themselves. The archaea cells live in the
spaces between the tiny tubes, and the colonies of
archaea and tubes look like flakes in the liquid
where they're growing.
Here's a nice site: