Cellular Nucleus

The nucleus is the core of a eukaryotic cell. Its primary function is to separate events inside from the cytoplasm outside. This separation of space and time supports the careful choreography of the detailed molecular dance happening inside the nucleus.

A non-dividing nucleus (in a state) "resting," is actually making the molecules which allow the rest of the cell to function. One of the most important events taking place in the nucleus is transcription, which is the transfer of the instructions on the DNA to the RNA. DNA is a stable store of genetic information, which must be transcribed (via RNA molecules) to construct the proteins coded in its blueprint.

Messenger RNA makes a "mirror image" copy of a stretch of the DNA molecule and then moves RNA out of the nucleus through the nuclear pores into the cytoplasm. There the RNA locates the ribosomes where it consumes the protein products with the help of transfer RNA molecules.

Prior to cell division, the nucleus replicates itself so that the two new cells will each contain genetic information. Several nuclear enzymes coordinate the replication of DNA. During cell division, the nuclear envelope breaks down, and equal copies of DNA and cytoplasm are partitioned into two daughter cells. After division, the nuclear envelopes reform in each daughter cell around its own copy of DNA. This fundamental sequence of events allows for the continuation of eukaryotic life during embryonic development and cellular regeneration throughout life.