 The nuclear envelope , otherwise known as nuclear membrane , consists of two cellular membranes , an inner and an outer membrane , arranged parallel to one another and separated by 10 to 50 <unk> ( nm ) . The nuclear envelope completely encloses the nucleus and separates the cell 's genetic material from the surrounding cytoplasm , serving as a barrier to prevent macromolecules from <unk> freely between the nucleoplasm and the cytoplasm . The outer nuclear membrane is continuous with the membrane of the rough <unk> <unk> ( <unk> ) , and is similarly studded with ribosomes . The space between the membranes is called the <unk> space and is continuous with the <unk> <unk> . 
