Final answer:
The transcriptional start on DNA corresponds to the 5' untranslated region (5' UTR) on mRNA, which is vital for regulation and the gene expression process.
Step-by-step explanation:
The transcriptional start on DNA is the same as the 5' UTR on mRNA. This region is also known as the 5' untranslated region, which is located just upstream of the protein-coding region in an mRNA molecule. The 5' UTR plays a significant role in the regulation of translation initiation and is essential for the proper expression of genes.
During transcription, RNA polymerase binds to the promoter region, initiates transcription at the transcription start site and synthesizes mRNA in a 5' to 3' direction. Ultimately, additional processing elements such as a 5' cap and a poly-A tail are added to the primary mRNA transcript to protect it and aid in its export from the nucleus.