Necleus is the centre of the regulation of cell activites since it contains the hereditary material. DNA carrying the information for protein synthesis. The DNA is bound up with histone protein to form chromatin. The nucleus contains one or more nucleoli in which ribosome subunits. ribosomal RNA,and transfer RNA are manufacturen. The nucleus is surroundud by a double nuclear membrane. crossed by a number of nuciear pores. The nucleus is continuous with the endoplasmic reticulum. there is uaually only one nucleus per cell. although there may be many in very large cells such as those of striated ( skeletal) muscle. Such multinucleate cells are called coenocytes.