module 7

• Bacteria are the smallest known cells.

  These tiny organisms live almost

  everywhere.

  
• The following are some characteristics of

  bacteria:

  -no nucleus

  -circular DNA shaped like a twisted rubber

  band

  -no membrane-covered (or membrane-

  bound) organelles

  -a cell wall outside the cell membrane and

  with a capsule

  -a flagellum (plural, flagella), a tail-like

  structure that some bacteria use to help

  them move.

  
• Archaea

  -They live in places where no

  other organisms could live

  (extreme/harsh conditions) such

  as boiling water or hot spring,

  volcanic vents, salty water.

  
• Archaea

  - (singular, archaeon) and

  bacteria share the following

  characteristics:

  - no nucleus

  -no membrane-bound organelles

  - circular DNA

  -a cell wall