The nuclear membrane is the "envelope" surrounding the cell's nucleus. It is a double lipid bilayer. Inside the nucleus, is the chemical known as DNA, which is the hereditary material. It makes up the chromosomes and genes. These never leave the cell's nucleus. However, the pores do allow a different substance known as RNA(ribonucleic acid) to travel out of the nucleus, to the cytoplasm. This is because a type of RNA called messenger RNA can copy or transcribe the DNA genetic code in a process called transcription. This mRNA can then travel to the cytoplasm and attach to a ribosome, which is the site of protein synthesis. Here, translation occurs and according to the mRNA transcript, a protein is assembled. Once it has been manufactured, it will detach and fold into a functional shape, to be transported either inside or out of the cell where it is needed. The job of the nuclear membrane in conclusion is that it is a barrier separating the contents of the nucleus from the cytoplasm. However, due to the pores, these regulate the exchange of materials between the nucleus and cytoplasm including--RNA and transcription factors.