Question

Why can transcription and translation be simultaneous in prokaryotes but not in eukaryotes?

Answer 1

In a prokaryotic cell, transcription and translation are coupled; that is, translation begins while the mRNA is still being synthesized.

Prokaryotic cells do not have a nucleus to separate things out, so DNA replication, transcription, and translation all occur at the same place. Transcription and translation frequently occur simultaneously in prokaryotic cells.

In eukaryotic cells, transcription occurs in the nucleus, and translation occurs in the cytoplasm.

This is impossible in eukaryotes, where transcription occurs in a membrane-bound nucleus while translation occursoutside the nucleus in the cytoplasm.

eukaryotic transcription and translation are spatially and temporally isolated.

Eukaryotic RNAs contain introns and exons and must be edited before translation can begin. The eukaryotic nucleus therefore provides a distinct compartment within the cell, allowing transcription and splicing to proceed prior to the beginning of translation. Thus, in eukaryotes, while transcription occurs in the nucleus, translation occurs in the cytoplasm.