However, recall that DNA molecules actually exist predominantly as the double stranded form. So we have our double helix basically in DNA our two single strands of DNA align antiparallel and they hydrogen bonds to form our double helix. But the RNA exists predominantly in the single strand form and this is exactly what allows our RNA molecule to actually pass through the nuclear pores. So unlike DNA which stays within the nucleus of our cell mRNA molecules can actually move from the nucleus to the cytoplasm through the nuclear pores that are found inside the nuclear membrane of the nucleus. Now as we mentioned earlier, there are different types of RNA molecules that exist and each one of these RNA molecules serves its own primary purpose. So let's discuss the different types of RNA molecules and what their primary function is.