Nucleolus

[Cheman]

What is the function of the nucleolus? I read somewhere that it produces ribosomal rna - if this is the case how does it do this? Is the nucleolus composed of dna which forms chromosomes like the rest of the nucleus?
Thanks. :-)

[Dagenais]

Yes, the nucleolus makes ribosomes.

This website (http://cellbio.utmb.edu/cellbio/nucleus3.htm) can explain it better.



The nucleolus is organized from the "nucleolar organizing regions" on different chromosomes. A number of chromosomes get together and transcribe ribosomal RNA at this site. The nuclear organizing (NO) regions are seen as circular areas (pale) surrounded by a rim of electron dense filaments. These filaments collectively are called the pars fibrosa (PF). This is formed from newly transcribed ribosomal RNA. This diagram shows the parts of the nucleolus.