AP BIOLOGY

Detailed explanation-1: -Proteins are sorted into the regulated secretory pathway in the trans Golgi network, where they are packaged into specialized secretory vesicles. These secretory vesicles, which are larger than other transport vesicles, store their contents until specific signals direct their fusion with the plasma membrane.

Detailed explanation-2: -The organelle that packages proteins before they leave the cell is the Golgi apparatus. The Golgi apparatus will receive proteins from the endoplasmic reticulum via its cis face, and then package them and modify them in various ways.

Detailed explanation-3: -Protein cargo moves from the ER to the Golgi, is modified within the Golgi, and is then sent to various destinations in the cell, including the lysosomes and the cell surface. The Golgi processes proteins made by the endoplasmic reticulum (ER) before sending them out to the cell.

Detailed explanation-4: -COPII-coated vesicles transport cargo proteins from the ER to the Golgi; COPI-coated vesicles transport cargo in the retrograde direction (from the cis-Golgi back to the ER) and between Golgi cisternae; and clathrin-coated vesicles form from the plasma membrane and the TGN to fuse with endosomes or lysosomes (Fig.

Detailed explanation-5: -Golgi bodies receive the proteins produced by the endoplasmic reticulum. It helps in the packaging and transportation of these proteins to various parts of the cell. Hence, it is called the post office of the cell.