Which of the following best describes the function of ribosomes?

Ribosomes play a crucial role in the process of protein synthesis, making them essential to cellular function. They are the cellular machinery where translation occurs, which is the phase of gene expression where messenger RNA (mRNA) is decoded to produce polypeptides or proteins.

During protein synthesis, ribosomes read the sequence of codons in the mRNA and facilitate the binding of transfer RNA (tRNA) molecules that carry specific amino acids. As the ribosome moves along the mRNA strand, it links amino acids together in the correct order, forming a polypeptide chain that will fold into a functional protein.

This process is vital for the growth, repair, and maintenance of cellular structures, as well as for the production of enzymes and hormones, which are critical for various biological functions. Thus, the primary function of ribosomes directly aligns with the concept of protein synthesis, distinguishing it from the other choices which pertain to different cellular functions.