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.
simple squamous epithelium is a single layer of flat scale-shaped cells. Both the endothelial lining of blood vessels and the mesothelial lining of the body cavities are simple squamous epithelium. Try to identify the simple squamous epithelia in these pictures.