The Central Dogma in eukaryotic cells
In eukaryotes (organisms with a nuclear membrane), DNA undergoes replication and transcription in the nucleus, and proteins are made in the cytoplasm. RNA must therefore travel across the nuclear membrane before it undergoes translation. This means that transcription and translation are physically separated. The primary transcript, heterogeneous nuclear RNA (hnRNA), undergoes extensive post-transcriptional processing to make a messenger RNA (mRNA)molecule that can pass through the nuclear membrane.
Figure © 1996 by Griffiths et al. ; text © 2008 by Steven M. Carr