The nucleus of a eukaryotic cell contains the DNA, the genetic material of the cell. The DNA contains the information necessary for constructing the cell and directing the multitude of synthesis tasks performed by the cell in the process of life and reproduction.he nucleolus is the central portion of the cell nucleus and is composed of ribosomal RNA, proteins and DNA. It also contains ribosomes in various stages of synthesis. The nucleolus accomplishes the manufacture of the ribosomes.