Every eukaryotic cell has two main parts, the nucleus and the cytoplasm. The nucleus guides the life processes of the cell by issuing three types of instructions. First, the nucleus directs cellular reproduction, where a cell divides into two new cells. Second, the nucleus controls a cell's differentiation during the development of the organism. Third, the nucleus, regulates the metabolic activities of the cell. The nucleus is the largest, most prominent structure within a cell and its presence within a cell distinguishes the cell as being eukaryotic, meaning "possessing a true nucleus," versus being prokaryotic, meaning "lacking a true nucleus." Whereas eukaryotic nuclear materials are bounded by a membrane, called the nuclear membrane, prokaryotic nuclear materials are not.
