So basically, what happens is once our proteins are synthesized within our Er, then they travel into the Golgi apparatus. And the Golgi apparatus is a series of membrane bound sacks that functions as packaging and sorting center of our cell. It packages sorts as well as modifies proteins before they actually secreted by that cell. Now, proteins that leave our Golgi apparatus, once they are modified, leave in little sections, little structures known as secretory vesicles. And these are shown by these blue vesicles here. So once our protein is modified, for example, we add some type of sugar onto the protein.