What is the primary function of the nucleus in eukaryotic cells?

The primary function of the nucleus in eukaryotic cells is to house genetic material and regulate gene expression. The nucleus contains the cell's DNA, organized into chromosomes, which carry the instructions for building and maintaining the organism. This genetic material is crucial for the development, functioning, and reproduction of cells.

In addition to housing DNA, the nucleus plays a vital role in regulating gene expression. This involves controlling which genes are turned on or off, thereby influencing the production of specific proteins needed for various cellular functions. The process begins in the nucleus where transcription occurs, creating messenger RNA (mRNA) from the DNA template. This mRNA then exits the nucleus and is translated into proteins in the cytoplasm.

The other functions listed in the question are associated with different organelles or cellular processes. For example, ATP production primarily occurs in mitochondria, lipid storage takes place in lipid droplets, and ribosomes are responsible for protein synthesis rather than the nucleus itself. Thus, the nucleus stands out as the critical site for managing the genetic blueprint of the cell and orchestrating its activities through gene regulation.