single-celled organisms that have a relatively simple structure. Prokaryotic cells are surrounded by a plasma membrane, but they have no internal membrane-bound organelles within their cytoplasm.

Bacteria are amongst the simplest of organisms – they are made of single cells. Their cell structure is simpler than the cells of animals, plants and fungi.

Other less powerful microscopy techniques coupled with organelle-specific stains have helped researchers see organelle structure more ... the DNA of prokaryotic cells is distributed loosely ...

Eukaryotes are thought to have originated through a process known as endosymbiosis, in which an ancestral prokaryotic cell engulfed ... a specific function critical to the cell's survival (Table 1).