* The nuclear envelope is a discontinuous double-membrane.
The gaps in the envelope are called nuclear pores.
The nucleus lies within the nuclear envelope
It is the largest organelle in eukaryotic cells (approximately five micrometers in diameter and visible under a light microscope).
The nucleus is the site of DNA replication and RNA synthesis (transcription).
Chromatin, the uncondensed form of DNA, resides in the nucleus
A nucleolus – nuclei can contain one or more of these nonmembranous organelles; cells that produce a large amount of proteins have a proportionally large nucleolus (and a large number of ribosomes).
rRNA resides within the nucleolus where it is synthesized; ribosomal proteins assemble in the nucleolus before maturing in the cytoplasm.