Attached ribosomes produce different types of proteins that are exported outside the cell such as digestive enzymes, polypeptide hormones, and cell signaling molecules. They also include ion channel proteins, which are incorporated within the plasma membrane. Some proteins produced by attached ribosomes are placed in membrane-bound vesicles and transported through the Golgi complex to the plasma membrane, from where they are released into the extracellular environment via exocytosis.