Bacteria are single-celled organisms with no nucleus. Making them the simplest form of life.
The eubacteria make up the Monera kingdom and archaebacteria make up the archaeal kingdom.
Eubacteria compose one of the three main domains of life. The other two being archaea and eukarya. They are classified within their own kingdom due to their chemical composition.
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Cocci (plural) or coccus (singular) are round bacterial cells.
bacilli (plural) or Bacillus (singular) are rod-shaped or elongated bacterial cells.
There are two types of spiral-shaped bacterial cells. Those that are rigid are called spirilla and then ones that are flexible are called spirochetes.
