Final answer:
The nuclear envelope contains two membranes, an inner and an outer membrane, both made up of phospholipid bilayers. These membranes are continuous with the rough endoplasmic reticulum and contain nuclear pores for material exchange.
Step-by-step explanation:
The Nuclear Envelope
The nuclear envelope is a double-membrane structure that constitutes the outermost portion of the nucleus. It is essential in separating the contents of the nucleus, which includes the genetic material, from the cytoplasm. This structure is made up of two phospholipid bilayers—an inner membrane and an outer membrane. The outer membrane is connected to the rough endoplasmic reticulum, and their lumen is continuous. The nuclear envelope's membrane is perforated with nuclear pores that regulate the transport of molecules such as RNA and proteins, ensuring that they can move between the nucleoplasm and the cytoplasm, while maintaining the environment necessary for the genetic material.