Ribosomes play a critical role in the process of protein synthesis, which is essential for numerous cellular functions. They are the cellular structures where translation occurs, directing the assembly of amino acids into polypeptide chains to form proteins based on the sequence of nucleotides in messenger RNA (mRNA). These proteins are then folded into their functional three-dimensional shapes and can serve various roles, such as enzymes, structural components, or signaling molecules.
The other options highlight important cellular functions, but they do not pertain to the primary role of ribosomes. For instance, modifying and sorting proteins is primarily the task of the endoplasmic reticulum and Golgi apparatus, while providing structural support is typically managed by cytoskeletal elements. Moreover, transporting materials usually involves vesicles and the endoplasmic reticulum or Golgi apparatus, rather than ribosomes themselves.