Which of the following sequences represents the order in which a protein made in the rough endoplasmic reticulum might move through the endomembrane system?

• A. Lysosome → plasma membrane
• B. Golgi apparatus → mitochondria
• C. Plasma membrane → nuclear envelope
• D. Nuclear envelope → lysosome
• E. Golgi apparatus → lysosome

Answer: (E)

Verified step by step guidance

1. Begin by understanding the role of the rough endoplasmic reticulum (ER) in protein synthesis. Proteins are synthesized by ribosomes attached to the rough ER, where they enter the ER lumen for folding and modification.
2. Next, recognize that proteins synthesized in the rough ER are typically transported to the Golgi apparatus. The Golgi apparatus is responsible for further modifying, sorting, and packaging proteins for their specific destinations.
3. After processing in the Golgi apparatus, proteins can be directed to various locations within the cell. One common destination is the lysosome, an organelle involved in digestion and waste processing.
4. Understand that the endomembrane system is a series of interconnected structures within the cell, including the ER, Golgi apparatus, lysosomes, and the plasma membrane, which work together to transport proteins and other molecules.
5. Finally, identify the correct sequence for the movement of a protein through the endomembrane system: from the Golgi apparatus to the lysosome, as this pathway is involved in targeting proteins for degradation or recycling within the cell.