What is the primary function of ribosomes in protein synthesis?

The primary function of ribosomes in protein synthesis is translating mRNA into polypeptides. Ribosomes act as the molecular machines that read the sequence of nucleotides in messenger RNA (mRNA) and use that information to assemble the corresponding amino acids in the correct order to form a polypeptide chain, which ultimately folds into a functional protein.

Ribosomes consist of ribosomal RNA (rRNA) and proteins, and they facilitate the interaction between mRNA and transfer RNA (tRNA), ensuring that the genetic code is accurately translated into a protein. This process is critical for gene expression and the overall function of cells.

In contrast, the other options describe different aspects of molecular biology that do not specifically pertain to the ribosomes' role during protein synthesis. Encoding genetic information relates to DNA and its transcription into mRNA, while carrying amino acids to the ribosome is the function of tRNA, not the ribosome itself. Modifying proteins after synthesis typically involves post-translational modifications, which occur after translation and are not performed by ribosomes but rather by various enzymes within the cell.