Cells are broadly divided into prokaryotic cells and eukaryotic cells, according to whether their genetic materials are enclosed by a nuclear envelope or not.
- Prokaryotic (pro-primitive, karyon-nucleus) cells are the most primitive cells. They do not contain a definite nucleus
- They are comparatively smaller.
- The cells have very simple organization.
- Cell organelles are absent.
- The chromatin bodies remain scattered inside the cytoplasm. Such a type of nucleus without a nuclear membrane is called a nucleoid.
- eg. Bacteria, Blue-green algae, Mycoplasma, PPLO (Pleuro Pneumonia Like Organisms), etc.