The Nucleus: Control Center of the Cell:
The nucleus of the cell contains its genetic material. Here is where the DNA is stored that contains the “information” the cell uses to make its proteins. Since these proteins make up much of the internal structure of the cell and (in the form of enzymes) control its metabolism, the nucleus is often referred to as the “control center” of the cell. A cell cannot survive for very long without its nucleus. (Red blood cells or
erythrocytes lose their nuclei as they mature; as you would expect, a mature erythrocyte does not live for very long.)
The nucleus of a eukaryotic cell.
The nucleus is surrounded by a
nuclear envelope (or
nuclear membrane) that is virtually identical in makeup to the plasma membrane that surrounds the cell itself. In fact, the nuclear envelope and the plasma membrane are actually continuous with each other, but we’ll get to that in a bit.
Just as the plasma membrane determines what gets in and out of a cell, the nuclear envelope determines what passes into and out of the nucleus of the cell. One distinction between the nuclear envelope and the plasma membrane is that the nuclear envelope has numerous relatively large holes in it known as
nuclear pores. These pores allow relatively large molecules such as proteins and RNA to cross the nuclear envelope.
The Nucleus
Linear Mode
