Which structure is known as the brain of the cell?

The nucleus is referred to as the brain of the cell because it serves as the control center that houses the cell's genetic material (DNA) and regulates various cellular functions. It is responsible for overseeing processes such as growth, metabolism, and reproduction by controlling the synthesis of proteins through the regulation of gene expression. The nucleus coordinates activities in the cell, making it pivotal for maintaining the cell's integrity and directing its actions in response to various internal and external cues. Additionally, the presence of the nuclear envelope protects the genetic material and facilitates the transportation of materials that are essential for communication between the nucleus and the cytoplasm. This central role in managing cellular functions justifies the analogy of the nucleus being the "brain" of the cell.