The new mRNA strands are made by the process called transcription that involves an enzyme that helps to copy a segment of DNA or gene to produce a new RNA strand that encodes for the protein. In this process, a new RNA strand copied the complementary to the sequence of DNA strand. It means adenosine is copied into its complementary form uracil in RNA, Thymin to adenosine, cytosine to guanine and guanine to cytosine.
