The nucleus is a large organelle located in the central part of the cell. It is a fairly large, spherical-shaped organelle that contains the nucleolus and the DNA of the cell. The DNA is the genetic blueprint for the cell. It codes for every trait and characteristic the cell possesses. It is what makes the cell unique, because there are no exact duplications among DNA sequences. The only known exact duplications occur among identical twins, because their
DNA comes from a zygote that divides into two zygotes, each having the same, identical genetic code.
The nucleolus is another spherical-shaped organelle. It is located within the nucleus, suggesting it is somewhat smaller than the nucleus itself. The nucleolus is the site of ribosomal RNA, which constructs ribosomes. Ribosomes are the smallest, most abundant organelles in the cell. They are responsible for the manufacture of proteins for the cell.
The nucleolus is inside the nucleus and contains RNA.