Final answer:
The nucleus functions to contain the cell's DNA and to regulate the synthesis of ribosomes and proteins, thus acting as the cell's control center.
Step-by-step explanation:
The function of the nucleus in a cell is primarily to house the cell's DNA and to direct the synthesis of ribosomes and proteins. It is considered the control center of the cell because it regulates all genetic instructions essential for the manufacturing of cellular proteins. Housed within a membrane called the nuclear envelope, which contains pores for molecular trafficking, the nucleus contains chromatin and the nucleolus, where ribosomes are synthesized. During cell division, chromatin condenses into chromosomes.