The most visible structure within the nondividing nucleus is the nucleolus . Roughly spherical region in the nucleus of nondividing cells, which consists of and ribosomes in various stages of production. May be two or more per cell. RNA produced elsewhere in the nucleus. Ribosomal proteins produced and imported from the cytoplasm.
Ribosomal subunits pass through nuclear pores to the cytoplasm, where their assembly is completed.