Nuclear envelope

Definition

The nuclear envelope is a double-membrane structure that encloses the nucleus, separating it from the cytoplasm. It functions to protect the genetic material and regulate the flow of molecules in and out of the nucleus.

5 Must Know Facts For Your Next Test

1. The nuclear envelope consists of two lipid bilayers: an outer membrane and an inner membrane.
2. Nuclear pores are embedded in the nuclear envelope, allowing selective exchange of substances between the nucleus and cytoplasm.
3. The outer membrane of the nuclear envelope is continuous with the endoplasmic reticulum.
4. The nuclear lamina, a dense network of proteins, provides structural support to the nuclear envelope from its inner side.
5. During mitosis, the nuclear envelope disassembles and reassembles to allow chromosome segregation.

Review Questions

• What is the primary function of the nuclear envelope?
• How do molecules typically move between the nucleus and cytoplasm?
• What happens to the nuclear envelope during cell division?

Related terms

Nucleus: Membrane-bound organelle that houses genetic material (DNA) in eukaryotic cells.

Nuclear Pore Complex: Large protein complexes that span both membranes of the nuclear envelope allowing transport of molecules.

Endoplasmic Reticulum: A network of membranous tubules within eukaryotic cells involved in protein and lipid synthesis; continuous with outer membrane of nuclear envelope.