Translation occurs on which cellular structures?

Translation is the process by which messenger RNA (mRNA) is decoded to produce a specific polypeptide or protein. This critical process occurs at ribosomes, which are the cellular structures responsible for synthesizing proteins. Ribosomes can either be found freely floating in the cytoplasm or bound to the endoplasmic reticulum, creating what is known as rough endoplasmic reticulum.

During translation, ribosomes facilitate the assembly of amino acids based on the sequence of codons in the mRNA, using transfer RNA (tRNA) to bring the appropriate amino acids in line with the mRNA sequence. The ribosome moves along the mRNA, reading the code and catalyzing the formation of peptide bonds between amino acids, ultimately leading to the formation of functional proteins that are vital for various cellular functions.

While the endoplasmic reticulum is involved in the process of protein synthesis (particularly when considering post-translational modifications and protein folding), the actual translation phase occurs at the ribosomes themselves. Therefore, ribosomes are the primary site of translation, making it the correct answer to the question.