The primary role of ribosomes in a cell is to synthesize proteins, which are essential for numerous cellular functions. Ribosomes facilitate the translation of messenger RNA (mRNA) into polypeptide chains, following the genetic instructions encoded in the mRNA. They can be found freely floating in the cytoplasm or attached to the endoplasmic reticulum (creating rough ER). Ribosomes are crucial for cell growth, repair, and maintaining cellular activities, making them fundamental components of all living cells.