Final answer:
The Golgi apparatus, near the cell's nucleus, processes, sorts, and packages proteins and lipids, functioning like a cellular post office. It is composed of stacked cisternae that modify contents delivered from the RER before dispatching them to various cell destinations.
Step-by-step explanation:
The Golgi apparatus, also known as the Golgi complex or Golgi body, is a critical organelle in eukaryotic cells. Located close to the nucleus, it functions much like a post office within the cell. The Golgi apparatus consists of flattened, stacked sacs or cisternae. It plays a central role in modifying, sorting, and packaging proteins and lipids for both intracellular use and secretion. Proteins and lipids are delivered to the Golgi complex in vesicles which bud off from the rough endoplasmic reticulum (RER). On the receiving (cis) face, these vesicles fuse with the Golgi membranes. Inside the Golgi, proteins may have carbohydrates added or modified, a process known as glycosylation, and then are sorted and packaged into new vesicles that bud from the opposite (trans) face. Depending upon their contents and destination, these vesicles may transport their cargo to the cell surface for export, to lysosomes or peroxisomes for digestion or metabolism tasks, or to other locations within the cell.