Draw a labelled schematic structure of a transcription unit. Explain the function of each component of the unit in the process of transcription.

Explanation

Transcription Unit: The promoter, the structural gene as well as a terminator are 3 regions included in transcription unit of DNA There are two strands of DNA having opposite polarity. The DNA dependent RNA polymerase enzyme catalyse polymerization in only direction that is 5-3 in one strand Strand with 3-5 polarity acts as a template: hence known as template strand: the strand with 53 polarity is coding strand.

Moreover, promoter lies towards 5' end upstream of the structural gene. This is a DNA sequence that provides binding site for the enzyme RNA polymerase Terminator lies towards 3' end downstream of coding strand and shows the end of transcription. There may occur some more sequences, they may be present downstream or upstream of promoter.
Template strand : 3 - ATGCATGCA-5
Coding strand : 5 - TACGGTAGT-3.