intracellular membrane-bounded organelle nucleus PMID:29100657 PMID:29357350 PMID:23405188 PMID:28976975 GO:0005634 ISBN:9780070316607 Planarian_Anatomy PMID:25404302 PMID:26457503 A membrane-bounded organelle of eukaryotic cells in which chromosomes are housed and replicated. In most cells, the nucleus contains all of the cell's chromosomes except the organellar chromosomes, and is the site of RNA synthesis and processing. In some species, or in specialized cell types, RNA metabolism or DNA replication may be absent. https://orcid.org/0000-0003-2569-1939 | https://orcid.org/0000-0002-7535-4407