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Definition

noun

The double-layered membrane surrounding the nucleus of a eukaryotic cell, separating the nucleoplasm from the cytoplasm.

Supplement

It is made up of two layers, each composed of a lipid bilayer. It is perforated with holes, called nuclear pores, to facilitate and regulate the exchange of materials (for example, proteins and RNA) between the nucleus and the cytoplasm. In between these two membranes is a space called perinuclear space.

Word origin: nucleo- from nucleus + Greek lemma, husk.

Synonyms:

• nuclear envelope
• nuclear membrane
• karyotheca