- The main role of the cell nucleus in cellular physiology is the storage of genetic material.
- The nucleus houses the cell’s DNA, which contains the instructions required for all cellular activities and inheritance.
- This genetic information is organized into chromosomes and is crucial for the regulation of growth, development, and reproduction of the cell.

- While the nucleus is involved indirectly in regulating cellular metabolism through gene expression, its primary and most essential function is to serve as the repository of the cell’s genetic code.
- Energy production via ATP synthesis occurs in the mitochondria, not the nucleus. Similarly, although proteins are synthesized in the cytoplasm by ribosomes, the nucleus contains the DNA that encodes for these proteins and controls protein synthesis by transcribing messenger RNA.

In summary, the cell nucleus acts as the control center of the cell by storing and protecting genetic material that governs cellular function and heredity.

Reference: Molecular Biology of the Cell, 6th Edition, Chapter 4: The Nucleus