The part of a eukaryotic cell that contains the genetic material. It is enclosed in a * nuclear membrane. Prokaryotic cells have no nucleus as such. The interphase nucleus of eukaryotic cells contains a network of chromatin fibres, which become organized into * chromosomes prior to cell division. Apart from chromatin the substance of the nucleus (the nucleoplasm or karyoplasm) contains complexes and enzymes necessary for the replication of DNA and the synthesis of RNA molecules. One or more * nucleoli are present associated with specific regions of the chromosomal DNA, the * nucleolar organizers . |
