Final answer:
The Golgi apparatus distributes proteins and lipids made within cells from the cis face (receiving face) to the trans face (releasing face). It modifies, sorts, and tags these molecules for proper delivery within the cell.
Step-by-step explanation:
The Golgi apparatus distributes proteins and lipids made within cells from the receiving face to the releasing face. The receiving face of the Golgi apparatus is known as the cis face, and it is situated near the endoplasmic reticulum (ER). In contrast, the releasing face is known as the trans face, which is oriented towards the cell membrane.
Vesicles containing proteins and lipids bud from the ER and journey to the Golgi apparatus. Here, they fuse with the cis face and release their contents into the lumen for processing. During this process, proteins and lipids undergo modifications such as the addition of sugar molecules, producing glycoproteins and glycolipids. These modifications are essential for sorting, packaging, and tagging the molecules, which allows them to be routed to their proper destinations within the cell.
Once the proteins and lipids have been modified and tagged accordingly, they are then packaged into new vesicles that bud off from the trans face of the Golgi. These vesicles can then travel to and fuse with the plasma membrane or the membranes of other organelles, thus completing their distribution within the cell.