Membrane-Bound Organelles
Ribosomes can become membrane bound in the early stages of synthesization of proteins required by other organelle. In eukaryotic cells this occurs in the “rough ER” region of the endoplasmic reticulum (ER). Newly produced polypeptide chains are inserted directly into the ER via the ribosome undertaking vectorial synthesis. Then are transported through the secretory pathways to their destinations. Typically bound ribosomes produce proteins to be used within the plasma membrane or expelled from the cell by exocytosis.