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.
Mesothelium is simple squamous epithelium that lines the abdominal cavity, the pericardial cavity, and the thoracic cavity. Endothelium is simple squamous epithelium that lines the vascular system. Transitional epithelium is seen in the urinary tract. Transitional epithelium has dome shaped cells on the apical surface. Pseudostratified epithelium is a type of epithelium that has cells which all touch the basement membrane. Pseudostratified epithelium is only one cell layer thick.