The
nucleolus is an approximately spherical region within the
nucleus of
eukaryotic cells. It consists of
nucleolar organizers[?] and
ribosomal subunits. Nucleolar organizers are special regions on some
chromosomes that contain multiple copies of the genes encoding for
rRNA (ribosomal RNA), which is a functional part of the ribosomes which are involved in
protein biosynthesis. Following synthesis, the rRNA is attached to the ribosomal subunits in the nucleus before transport through the
nuclear pores into the
cytosol.
