Where does translation occur?

• A. Nucleus
• B. Ribosomes in the cytoplasm
• C. Mitochondria
• D. Nucleolus

Answer: (B)

Translation is the process of building a protein from mRNA using ribosomes. In eukaryotic cells, most protein synthesis happens in the cytoplasm, where ribosomes read the mRNA and assemble amino acids into a polypeptide. These ribosomes can be free-floating in the cytoplasm or attached to the rough endoplasmic reticulum, but either way the action is in the cytoplasm.

The nucleus is where transcription occurs, turning DNA into mRNA, so translation doesn’t happen there. The nucleolus is involved in making ribosomal RNA and assembling ribosome subunits, not in protein synthesis. While mitochondria have their own ribosomes for some mitochondrial proteins, the bulk of translation for cellular proteins takes place on cytoplasmic ribosomes.

So the best location is ribosomes in the cytoplasm.