Where do transcription and translation take place in eukaryotic cells?

• A. Transcription occurs in the nucleus; translation occurs in the cytoplasm on ribosomes.
• B. Transcription occurs in the cytoplasm; translation occurs in the nucleus.
• C. Transcription and translation both occur in mitochondria.
• D. Transcription occurs on ribosomes; translation occurs in the nucleus.

Answer: (A)

In eukaryotic cells, transcription happens in the nucleus where DNA resides, using RNA polymerase to synthesize RNA from the DNA template. The resulting mRNA is then processed and exported to the cytoplasm, where ribosomes translate it into a protein. This separation—transcription in the nucleus and translation in the cytoplasm on ribosomes—reflects how the cell organizes gene expression: the genetic information is copied in the nucleus and the protein-building machinery operates in the cytoplasm. While mitochondria have their own transcription/translation systems, the general, cell-wide arrangement is transcription in the nucleus and translation in the cytoplasm on ribosomes.