Final answer:
Proteins destined for secretion are directed to the rough ER by a signal peptide, modified in the Golgi apparatus, and then transported via secretory vesicles to fuse with the plasma membrane and release their contents outside the cell through exocytosis.
Step-by-step explanation:
The potential pathway followed by a protein destined for secretion involves a specialized sequence, initiating with the ribosomes translating mRNA into polypeptides. As the signal peptide emerges, it directs the protein to the endoplasmic reticulum (ER), specifically the rough ER (RER), where the protein enters the lumen and begins folding into its functional form. The protein is then encapsulated into transport vesicles that bud off and move towards the Golgi apparatus. In the Golgi, proteins are further modified, sorted, and tagged for their final destinations. Finally, secretory proteins are packaged into secretory vesicles that bud from the trans face of the Golgi and are eventually transported to the plasma membrane. Here, through the process of exocytosis, these vesicles fuse with the plasma membrane and release their contents to the exterior of the cell.