It also functions in cell communication as well as protecting the cell from outside sources of harm. Now, other types of eukaryotic cells, not all, but some eukaryotic cells, for example, plant cells, also contain an additional second protecting barrier known as the cell wall. The cell wall protects plant cells and it also gives them the shape and structure. Now let's move on to basically the organelle that defines the eukaryotic cell, known as the nucleus. The nucleus is basically an organelle that contains the genetic information and the nucleus contains its own phospholipid bilayer that is called the nuclear envelope or the nuclear membrane to differentiate it from the cell membrane. The nuclear membrane contains nuclear pores, very small openings that allow certain things into and out of that nucleus.