This site is intended for healthcare professionals

Go to /sign-in page

You can view 5 more pages before signing in


Last reviewed dd mmm yyyy. Last edited dd mmm yyyy

Authoring team

The nucleus is an organelle typically occupying about a tenth of the eukaryotic cell volume. It has a central role in gene expression, heredity and cell division by virtue of the presence of DNA. Indeed, the nucleus theoretically acts as a haven for precise interpretation of the genetic code away from the myriad of cytoplasmic functions.

There are a variety of proteins present which aid function e.g.:

  • DNA-binding proteins - histones
  • DNA polymerases
  • RNA polymerases
  • RNA transcript processing enzymes
  • gene regulatory proteins
  • ribonucleoprotein complexes containing messenger RNA

DNA may be stored in a variety of ways within the nucleus e.g. within chromosomes, chromatids, chromatin, nucleosomes, Barr body or nucleolus. The nucleolus has a special function as the origin of ribosomal RNA. All nuclear components are suspended in amorphous nucleoplasm - karyolymph - and enveloped by a specialised nuclear membrane.

A few cells have dispensed with the nucleus at the expense of function e.g. haemoglobin storage in the mature erythrocyte.

Related pages

Create an account to add page annotations

Add information to this page that would be handy to have on hand during a consultation, such as a web address or phone number. This information will always be displayed when you visit this page