Keeper of hereditary information.

Genetic information is stored in the nucleus of the eukaryotic cell. DNA is responsible for protein synthesis, cell division, and more. Each organism has a distinct set of chromosomes. When more or less chromosomes are transferred, mutations and genetic abnormalities appear. In prokaryotic cells there is no nucleus, but they have DNA, since all living organisms have hereditary information. And for prokaryotes, it simply moves around the cell, and is not surrounded by a shell. Such devices are less reliable, but prokaryotes exist in our time.