The nucleus contains all the DNA of a cell. RNA polymerase converts the DNA of the gene corresponding to the desired protein into RNA. The RNA is transported to the rough ER where it is translated into an amnio acid sequence with the aid of ribosomes and enzymes.This polypeptides are subsequently packed into vesicles and transported to the golgi apparatus where they are further modified. The vesicle containing mature proteins buds off of the golgi and travels to and fuses with the plasma membrane where the protein is released into the extracellular environment.