Define a cistron. Differentiate between monocistronic and polycistronic transcription units with suitable examples.

Explanation

Cistron is defined as a segment of DNA coding for a polypeptide.
Monocistronic transcription : Mostly in eukaryotes the structural gene in a transcription unit can be said to be monocistronic transcription.
The moncistronic structural genes have interrupted coding sequence - the genes in eukaryotes are split.
The coding sequence or expressed sequence are defined as exons.
Exons are said to be these sequence that appear in mature or processed RNA.
Exons are interrupted by introns.
Introns or intervening sequence do not appear in mature or processed RNA.
Polycistronic transcription : Mostly in prokaryotes, the structural gene in a transcription unit can be said to be polycistronic transcription.