A nuclear membrane is a bilayer membrane that encloses a nucleus in eukaryotic cells and thus surrounds the genetic material of the cell. It consists of two phospholipid bilayers with many small holes. Those holes allow different material, such as proteins, RNA, ATP, water, to move in and out of the nucleus. Therefore its function is to regulate the flow of RNA and proteins since DNA, which carries the genetic information of the cell, cannot leave the nucleus.