Eucaryote are any cell or organism that possesses a clearly defined nucleus, a description that excludes bacteria and blue-green algae. The eucaryotic cell has a nuclear membrane, well-defined chromosomes (bodies containing the hereditary material), mitochondria (cellular energy exchangers), a Golgi apparatus (secretory device), an endoplasmic reticulum (a canal-like communication system within the cell), and lysosomes (digestive apparatus within many cell types).

Excerpt from the Encyclopedia Britannica without permission.