Nucleus

The nucleus is like the brain of a cell. It contains the DNA of the cell, and orders it to build and destroy things. It tells the cell what to do and what not to do. Also, in the nucleus there is a suborganelle called a nucleolus. It produces ribosomes.

Many kinds of viruses will attack the nucleus by injecting their DNA into it, thus forcing it to create more viruses. This typically causes the cell to lyse.

Although most cells only have one nucleus, certain cells have more. These kind of cells are multi-nucleated.