What structure is involved in protein synthesis?

The ribosome is the structure involved in protein synthesis. Ribosomes are molecular machines found within all living cells that facilitate the assembly of amino acids into proteins based on the sequence of messenger RNA (mRNA). This process occurs in two stages: transcription, where the DNA sequence is copied into mRNA, and translation, where ribosomes read the mRNA sequence and link the appropriate amino acids together to form a polypeptide chain, which will fold into a functional protein.

In relation to the other structures, while the nucleus contains the cell's genetic material and is responsible for transcription, it is not directly involved in synthesizing proteins; it provides the instructions. Vesicles play a role in transporting materials within the cell, including proteins, but they do not synthesize them. Vacuoles are used for storage and do not participate in protein synthesis. Thus, ribosomes are uniquely positioned as the primary site of protein synthesis within the cell.