Here's why:

* Ribosomes are the protein synthesis factories of the cell. They read the genetic code carried by messenger RNA (mRNA) and use that information to assemble amino acids into proteins.

* Ribosomes can be found free-floating in the cytoplasm or attached to the endoplasmic reticulum (ER).

* Free ribosomes make proteins that will function within the cytoplasm.

* Bound ribosomes (those attached to the ER) make proteins that will be secreted from the cell or incorporated into membranes.

While other organelles play a role in protein modification, transport, and function, the ribosomes are the primary location for protein synthesis.