During translation, where does protein synthesis take place?

• A. At a ribosome
• B. In the nucleus
• C. In the Golgi apparatus
• D. In the mitochondrion

Answer: (A)

Protein synthesis during translation occurs at a ribosome. The ribosome is the molecular machine that reads the messenger RNA sequence and uses transfer RNAs to add the corresponding amino acids, forming a polypeptide chain. In eukaryotic cells, this happens either in the cytoplasm or on the rough endoplasmic reticulum. The nucleus houses transcription, not translation, while the Golgi apparatus processes and ships proteins after they’re made. Mitochondria can make some proteins with their own ribosomes, but the general site for protein synthesis is the ribosome.