The Nucleus

Nucleus with Nuclear Pores © Dennis Kunkel

The nucleus is the control center of a cell. It contains the cell's hereditary information (DNA) and controls the cell's growth and reproduction.

The nucleus also controls the synthesis of ribosomes and proteins in the cytoplasm.

Looking at the nucleus from under an electron microscope, it appears as a distinct, circular object enclosed in a membrane. This membrane, called the nuclear envelope, separates the contents of the nucleus from the cytoplasm.