What is the main role of the nucleus in a cell?

The primary function of the nucleus in a cell is to house and protect the cell's genetic material, which consists of DNA. This essential organelle serves as the control center for cellular activities by regulating gene expression and facilitating the replication of DNA during the cell cycle. Within the nucleus, the DNA is organized into chromosomes, and it is surrounded by a double membrane known as the nuclear envelope, which protects the genetic material from damage and regulates the movement of molecules in and out of the nucleus.

Additionally, the nucleus is where processes like transcription occur, where segments of DNA are transcribed into messenger RNA (mRNA), which eventually leads to protein synthesis in the cytoplasm. Thus, the nucleus not only safeguards the cell's hereditary information but also plays a crucial role in the regulation of cellular functions and the expression of traits.