Biology · CELL THE UNIT OF LIFE

In eukaryotic cells, secretory proteins synthesized on ribosomes attached to the rough endoplasmic reticulum undergo maturation in the Golgi apparatus. What is the precise directional path followed by these materials through the Golgi cisternae?

1. Fusion at the concave trans face followed by biochemical modification and discharge from the convex cis face.
2. Direct entry into both cis and trans faces simultaneously as they are structurally and chemically interconnected.
3. Vesicles from the ER fuse with the convex cis (forming) face, move through the cisternae, and are released from the concave trans (maturing) face.
4. Budding from the nuclear envelope directly into the maturing trans face without involvement of forming face.