Another name for prokaryotic cells is prokaryotes, simple life forms that consist of the kingdoms of Monera and Archaea. Prokaryotic is Greek for "before nucleus."
Prokaryotic cells are simple molecules surrounded by a membrane and cell wall, but they lack more complex elements of more advanced cells, such as organelles. Prokaryotes come in round, rod or helical shapes, known as cocci, baccilli, and spirilla or spirochetes, respectively. Prokaryotes have genetic information in either nucleolids or circular loops called plasmids. The kingdom of Monera refers to simple bacteria, and most prokaryotes are bacteria; Archaea are types of bacteria that survive in harsh environments. Archaea are found in extreme environments, and they consist of methanogens, halophiles and thermoacidophiles; these prokaryotes can be found in marshes, intestinal tracts, salty lakes and extremely acidic conditions.