At the chemical level, the DNA of prokaryotic cells, which have no nuclear membranes, and that of eukaryotic cells, which have separate, membrane-enclosed nuclei, is identical. DNA is a long, double-stranded molecule containing a backbone of repeating, alternating sugar and phosphate units.
Simple cuboidal epithelium is a type of epithelial tissue found in the body. It is a single layer thick and made of cube-shaped cells. This type of tissue is found lining parts of the body such as the kidney tubules and walls of respiratory bronchioles.
1 A stratified squamous epithelium is quite thick, with squamous cells on the surface overlying deeper layers of taller cells.  2 Cuboidal describes cells that are rather box-shaped, not flattened. 3  Cuboidal epithelial cells typically appear square or rectangular in cross section, with a round, centrally placed nucleus. Stratified signifies two or more layers of epithelial cells. 2  By convention, a stratified epithelium is described according to the shape of cells on its free surface. 3  Regardless of whether the surface cells are squamous, cuboidal, or columnar, the underlying cells are usually cuboidal.