The
Central Dogma in prokaryotic versus eukaryotic
cells
In
prokaryotes (organisms without a nuclear membrane), DNA undergoes replication and
transcription
and RNA undergoes translation
in an undivided compartment. All three processes can occur
simultaneously.
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.