Rough Endoplasmic Reticulum functions include which of the following?

• A. Lipid storage only
• B. Energy production
• C. DNA replication
• D. Synthesis, storage, transport, detoxification

Answer: (D)

The rough endoplasmic reticulum is defined by its ribosome-studded surface, which anchors the site of protein synthesis. The main role here is producing polypeptides that will be secreted, become part of a membrane, or be delivered to lysosomes. As these new proteins are synthesized, they enter the ER lumen where they fold and may receive initial modifications. The ER then packages these proteins into transport vesicles that ferry them toward the Golgi apparatus for further processing and sorting. Proteins can also be stored briefly in the ER lumen before they’re needed, contributing to its storage function. Detoxification elements are linked to the ER as well, since some detoxification processes involve enzymes associated with this organelle, especially in cells focused on metabolizing compounds. In sum, synthesis of proteins, their storage and trafficking, and related processing—and some detox roles—best describe the rough ER’s functions.