No, the nucleolus is contained within the nucleus of a cell, not the other way around.

Think of it like this:

* The nucleus is the "brain" of the cell. It contains the cell's genetic material (DNA).

* The nucleolus is a "little brain" within the nucleus. It's responsible for making ribosomes, which are essential for protein synthesis.

So, the nucleolus is a smaller structure located inside the larger structure called the nucleus.