Coding and non-coding regions of DNA, both are important. DNA can transcribe into mRNA, rRNA, tRNA and miRNA. Among these only mRNA codes for protein, rest are there to assist or regulate the translation. rRNA works as a catalytic component of ribosomes and tRNA helps in the transfer of amino acids in translation. miRNAs on the other hand are derived from non-coding regions and are unique in the sense that they may bind to a matching mRNA (seed sequence) and cleave them to repress translation. miRNAs can have their effect through various ways, including premature termination, and sequestration in P bodies. There are multiple studies in the literature to give a better idea of how exactly these RNAs work.

Additionally, it must be appreciated that the RNA, although single stranded, is never straight. It has foldings as you would see in proteins.

Gene Expression.

rRNA and mRNA facilitate translation and sRNA's act as regulatory mechanisms.