Final answer:
The mRNA from a vaccine should be targeted to the rough endoplasmic reticulum (RER) for protein synthesis, as it contains ribosomes that initiate this process before the proteins are sent to the Golgi apparatus for further modification.
Step-by-step explanation:
Target Organelle for mRNA Vaccine Synthesis
The mRNA from a vaccine should be targeted to the rough endoplasmic reticulum (RER) during its synthesis. The RER is studded with ribosomes, which are responsible for the synthesis of proteins. When the mRNA is delivered into the cytoplasm of the cell, ribosomes on the RER translate the genetic information to begin protein synthesis. These proteins can be glycosylated in the RER before they are transported to the Golgi apparatus for further modification and sorting. The smooth endoplasmic reticulum (SER), in contrast, is involved in lipid synthesis and detoxification processes and does not partake in protein synthesis. Therefore, for the synthesis of vaccine proteins, the RER is the correct target organelle.