Structural Basis of Cellular Information:
The Organization of Nucleus

Nucleus is the most prominent cell organelle in a eukaryotic cell, which determines not only cell survival but also the activities of cytoplasm, leading to cell specificity. It is now known that the nucleus exerts its control by virtue of its DNA. One of the advantages of having the genetic materials inside a membrane-bound organelle is that access to these materials and export of their products become controllable. For instance, cytosol contains many ions and proteins that could bind to and even covalently alter DNA and chromosome structures if they were not protected inside the nucleus.

Besides protection, nuclear envelope also governs the exit of the products of nuclear metabolism, particularly RNA. Transcription occurs in a compartment (nucleus) separated from translation (ribosomes in cytosol) in eukaryotes, which could serve as a mean of control over when an mRNA would prime the production of a protein.

Nucleus also has other prominent features that devote further studies. The most obvious is the existence of one or more nucleoli that are the factories of RNA synthesis. The rest of the material inside the nucleus is DNA complexed with proteins (chromatin), the RNA transcribed from DNA, and many other proteins unattached to DNA in the nucleoplasm. All these structures are then enclosed by a double membrane, the nuclear envelope.