The double-layered transparent membrane, which makes the outer covering of the nucleus is the nuclear membrane.
The outer membrane porous but the inner one is not. Chemically the membrane is made of protein and lipid.
Fig: Nuclear Membrane Structure
The main function of this membrane is to keep the nucleoplasm, chromosome and the nucleus distinct from the cytoplasm. Transportation and communication between internal materials and cytoplasm are also done through this membrane.
For transporting proteins and RNA in and out of the nucleus, Nuclear Membrane acts as a security check. In the process of mitosis and meiosis cell division, these membranes help to regulate the transport of minerals between the nucleus and cytoplasm.
It also controls the flow of information to the nucleus and DNA that are conveyed by the macromolecules.
Researchers are trying to investigate more aspects of the cell membrane so that they can comprehend the different features of this double-layered membrane much better.