What is the role of ribosomes in protein synthesis?

Ribosomes play a crucial role in protein synthesis by serving as the site where amino acids are assembled into proteins. They facilitate the translation process, which is the second step in gene expression. During translation, ribosomes read the mRNA (messenger RNA) sequence and guide the binding of appropriate tRNA (transfer RNA) molecules that carry specific amino acids.

The ribosome moves along the mRNA strand, catalyzing the formation of peptide bonds between adjacent amino acids, effectively linking them into a growing polypeptide chain. This process ultimately leads to the formation of a functional protein based on the genetic instructions encoded in the mRNA. Thus, the correct choice emphasizes the ribosome's essential role in building proteins from amino acids, making it a fundamental component of cellular biology.