The process by which the information form one strand of DNA is transformed to a new molecule of messenger RNA is called transcription. The genes of DNA which are also called the workhorses of the cell will encode protein molecules and allow them to carry all the necessary functions of life. Expressing a gene refers to the manufacture of the corresponding proteins. During transcription the genes of DNA nurse as template for complementary base-pairing and the formation of Pre-mRNA molecule is catalysed by an enzyme called RNA polymerase ii. The formed m-RNA is a single stranded copy of the gene which is next transformed into protein molecule. The m-RNA is read according to the genetic code which relates the sequence of DNA to the sequence of amino acids of the protein. This is how base pairing builds proteins from RNA.
