What is the difference between eukaryotic and procaryotic cells?

Procaryotic cells lack organelles (e.g. nucleus) and other internal membrane-bound structures (e.g. endoplasmatic reticulum). Most of their genetic material (i.e. DNA) forms an irregularly shaped structure, termed nucleoid (= nucleus-like), which sits in the cytoplasm of the prokaryotic cell. In contrast, the genetic material of eukaryotic cells is located within the nucleus and surrounded by a nuclear membrane. Therefore, the genetic material is separated from the rest of the cell.