In: Biology
The nucleus of many eukaryotic cells contains a structure called
a nucleolus. As the nucleus is the "brain" of the cell, the
nucleolus could loosely be thought of as the brain of the nucleus.
The nucleolus takes up around 25% of the volume of the
nucleus.
This structure is made up of proteins and ribonucleic acids (RNA).
Its main function is to rewrite ribosomal RNA (rRNA) and combine it
with proteins. This results in the formation of incomplete
ribosomes. There is an uninterrupted chain between the nucleoplasm
and the interior parts of the nucleolus, whichoccurs through a
system of nucleolarpassages. These passages allow macromolecules
with a molecular weight up to 2,000 kDato be easily circulated
throughout the nucleolus.
Because of its close relationship to the chromosomal matter of the
cell and its important role in producing ribosomes, the nucleolus
is thought to be the cause of a variety of different human
diseases.