Given the task definition and input, reply with output. In this task you will be given a text passage from a trivia quiz. You should choose the category this question belongs to from these categories: History, Science, Social Science, Fine Arts, Literature. You can only choose one category, so if in doubt, please choose the closest match.

This structure was originally thought to be an illusion caused by the black reaction, but its existence was proven by an electron microscope. The GAAP protein located in this structure protects against apoptosis, and its contents are transferred to its lumen. The COPII protein tags vesicles from another organelle which enter the cis face of this structure, which is made up of stacks of flat membrane-covered sacs known as cisternae. For 10 points, name this organelle that processes and packages proteins and lipids to be sent throughout the cell, named for its Italian discoverer.
Science