Final answer:
The missing organelle in the 'path of protein' production from ribosomes to the cell membrane is the Golgi apparatus, which is responsible for protein modification and packaging.
Step-by-step explanation:
Proteins are produced all the time in cells, and there is a specific pathway they follow from synthesis to export. After proteins are assembled by ribosomes, they move to the rough endoplasmic reticulum (RER), where they undergo modifications. The next step in the "path of protein" production after the rough ER is the Golgi apparatus, which organizes, modifies, packages, and tags the proteins for transport to their final destinations, including their insertion into the cell membrane or export out of the cell. Therefore, the correct answer to which organelle is missing in the path of protein production, ribosomes -> rough ER -> __________ -> membrane, is A) Golgi apparatus.