The Golgi apparatus is a vital organelle found in the cells of eukaryotic organisms. It functions primarily in modifying, sorting, and packaging proteins and lipids that are synthesized in the endoplasmic reticulum. The Golgi apparatus consists of a series of flattened, membrane-bound sacs called cisternae, which work together to process cellular materials. Once proteins and lipids are modified in the Golgi, they are sent to their final destinations, either within the cell or outside of it. This process is essential for maintaining cellular function and communication, as it ensures that the right molecules reach the right locations at the right times.