The double stranded helical DNA "unzips" and is transcribed, an accurate copy is made of the DNA template. The single stranded RNA has Uracil inplace of Thymine. An Adenine on the DNA strand will result in a Uracil on the RNA, Thymine for an Adenine, Cytosine for a Guanine, and Guanine for a Cytosine. The DNA stays in the nucleus while the RNA (mRNA, tRNA, rRNA) moves out of the nucleus and into the cytoplasm of the cell.