Why Transcription and Translation are Coupled in Prokaryotes
Coupling of transcription and translation means that ribosomes bind to the mRNA and protein synthesis (translation) begins while the mRNA is still being synthesized ( transcription )
Transcription and translation are coupled in prokaryotes because there is no nucleus to separate the processes of transcription and translation, when bacterial genes are transcribed, their transcripts can immediately be translated.
In eukaryotes, tanscription and translation occur in different cellular compartments separated by a membrane barrier — transcription occurs inside the nucleus and translation occurs in the cytoplasm.
Prokaryotic transcription occurs in the cytoplasm alongside translation and can occur simultaneously.
Transcription occurs where the DNA is, translation is done by ribosomes in the cytoplasm. Prokaryotes unlike eukaryotes have no karyon, meaning nucleus. Therfore prokaryotic genomic DNA is located in the cytoplasma. So when prokaryotic DNA is transcribed, ribosomes attatch to the mRNA and start transcription but at the same time already started to be translated. So transcription and translation are coupled. But in eukaryotes, the transscription is done in the nucleus, when the RNA is finished, it is processed (splicing, polyA etc. ) and transported to the cytoplasm where it is transcribed. So in eukayotes transcription and translation are not coupled….