The building block of life is the cell. The nucleus within is like a guiding light to the cell, a control center, the Command. Within this organelle are found the chromosomes with their many genes, the histones—united with DNA to form chromatin, as well as other loose structures, such as the nucleolus. What are the basic parts of the chromosomes, and how can such a large number of them fit within the nucleus? Articles by your Bright Hub contributors discuss, not only the makeup, but the functioning of the cell nucleus as well as that of its component parts.