Nuclear pore complex
Nuclear pore complex (about 120 nm in diameter) is made of nucleoproteins that assemble and span the nuclear envelope, thus creating an octagonal nuclear pore. The pore, itself, is about 9 nm wide and about 200 nm deep.
There are numerous nuclear pore complexes that form in thenuclear envelope, i.e. about two thousand in average. These pores allow the passage of molecules into and out of the nucleus. Examples of molecules that pass through these pores are ribonucleoproteins, DNA polymerases, lipids, signaling molecules, and carbohydrates.