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