Difference

First, the sugar in RNA is
ribose, which has one additional oxygen atom not present in DNAs sugar (deoxy-
ribose). Second, RNA has the base uracil in place of thymine. Uracil, like thymine,
forms base pairs with adenine. Third, RNA is a single strand of nucleotides, in
contrast to the double-stranded structure of DNA. This single-stranded structure
allows some types of RNA to form complex three-dimensional shapes. As a result,
some RNA molecules can catalyze reactions much as enzymes do.