Protein Synthesis

• Proteins are made at ribosomes.
• The ribosomes on the RER make proteins that are attached to the cell membrane.
• The free ribosomes in the cytoplasm make proteins that stay in the cytoplasm.
• New proteins produced at the RER are folded and processed in the RER.
• They are then transported from the RER to the Golgi apparatus in vesicles.
• At the Golgi Apparatus, the proteins are processed again (sugar chains are trimmed or more are added. 
• The proteins enter more vesicles to be transported around the cell. For example, glycoproteins move to the cell surface and are secreted from the cell.