Final answer:
The cis Golgi receives vesicles from the ER and initiates the modification process, whereas the trans Golgi completes the modifications and packages the molecules for their specific destinations. These processes are crucial for cellular function, especially in cells engaged in extensive secretory activities.
Step-by-step explanation:
The functions of the cis and trans Golgi are essential for the processing and sorting of proteins and lipids within a cell. The cis Golgi is known as the receiving side of the Golgi apparatus, where transport vesicles that form from the endoplasmic reticulum (ER) fuse and release their contents into the Golgi's lumen. In contrast, the trans Golgi functions as the outgoing side, where modified proteins and lipids are packaged into vesicles and sent to their final destinations, such as incorporation into the plasma membrane, secretion from the cell, or delivery to other organelles.
The modifications that occur within the Golgi apparatus include glycosylation, where short chains of sugar molecules are added, and phosphorylation, where phosphate groups are attached. These alterations often serve as sorting signals, directing the molecules to the correct location. Cells that are highly active in secretion, like those in the salivary glands or the immune system, contain an abundance of Golgi to facilitate these processes.