Prokaryote

Prokaryotes (or Monera) are some of the simplest living things.^[1] They are unicellular organisms and they include two major divisions of simple living beings: bacteria, and Archaea.^[2] They generally do not have a cell nucleus, nuclear membrane or cell organelles, however a small number of exceptions have been found. Prokaryotes possess genetic material in the form of a single DNA loop called a Nucleoid that floats around freely inside the cell. Bacteria include the Cyanobacteria (formerly known as blue-green algae due to their photosynthetic capacity).

Some form biofilms that are somewhat like multicellular organisms.

Besides a nucleus, prokaryotes lack other things eukaryotes (cells with a true nucleus) have. They reproduce without fusion of gametes. They do not have membranes. This means that there are no vacuoles, Golgi apparatus, endoplasmic reticula or other organelles inside the cell. However, they do have ribosomes, though of a simpler kind than eukaryotes. Eukaryote cells include organelles which were once free-living prokaryotes.

1. ↑ Excluding viruses
2. ↑ The word 'prokaryote' describes a type of cell. The name comes from Greek pro- (meaning before) and karion, meaning nut or kernel.