Which cell organelle are most closely associated with protein synthesis?

The cell organelles most closely associated with protein synthesis are ribosomes. Ribosomes can be found either floating freely in the cytoplasm or attached to the endoplasmic reticulum (rough ER). They facilitate the translation of messenger RNA (mRNA) into polypeptide chains, which then fold into functional proteins. Additionally, the rough ER plays a role in the modification and transport of these proteins.