The whole process can be imagined as an elaborate postal system. It begins with the linguistic code of genes (RNA) that is translated to write the letter (the protein). The protein is written, or synthesized, by the cell’s letter writer (the ribosome), which then posts it to the mailbox (the pore by which the protein enters the ER). The pore routes it to the central posting station (the endoplasmic reticulum), which then sends the letter to the sorting system (the Golgi), and finally brings it to the delivery vehicle (the secretory granule). There are, in fact, even codes appended to proteins
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