Final answer:
The Golgi apparatus has a cis face and a trans face. Transport vesicles from the ER fuse with the cis face, and proteins and lipids undergo modifications as they travel through the Golgi.
Step-by-step explanation:
The Golgi apparatus has two sides: the cis face and the trans face. The cis face is the receiving side, located near the endoplasmic reticulum (ER), while the trans face is the releasing side, towards the cell membrane. Transport vesicles from the ER fuse with the cis face of the Golgi apparatus, where they empty their contents into the lumen. As proteins and lipids travel through the Golgi, they undergo further modifications and are sorted to their proper destinations via tagging.