Final Answer:
The organelle that performs post-translational modifications on proteins and is involved in the packaging and shipping of molecules is the Golgi apparatus.
Step-by-step explanation:
The Golgi apparatus is a cellular organelle responsible for processing, modifying, and packaging proteins and lipids synthesized in the endoplasmic reticulum (ER). Proteins synthesized in the rough ER undergo post-translational modifications, such as glycosylation and phosphorylation, in the Golgi apparatus. This organelle consists of a series of flattened membrane-bound sacs called cisternae.
It has a cis face, where substances enter, and a trans face, where modified and packaged molecules exit in vesicles. The Golgi apparatus plays a crucial role in sorting and directing these vesicles to their specific cellular destinations, such as lysosomes, plasma membrane, or secretion outside the cell.