Question

(a) Describe the process of transcription in bacteria
(b) Explain the processing the hnRNA needs to undergo before becoming functional mRNA in eukaryotes.

Answer 1

a) Transcription in bacteria:

• Initiation: In this step, RNA polymerase enzyme along with initiation factor (sigma) binds with DNA sequence at promotor and starts the transcription.
• Elongation: In this step, RNA polymerase enzyme nucleoside triphosphate as a substrate and polymerises the nucleotides of tamplets as acomplementry strand.
• Termination: In this step terminator factor (rho) replaces the intiation factor at the termination point of DNA sequence.At this stage detachment of RNA and RNA polymerase enzyme with rho factor takes place.

b) hnRNA needs to undergo spicing before becoming functional mRNA in eukaryotes. hnRNA have both coding and non coding sequence and thus it undergo splicing where all the non coding (introns) are removed and all the coding (exons) are bind together and forms functional mRNA.