RNA is made up of four nucleotides adenylic acid, guanidylic acid, cytidylic acid, and uridylic acid. Adenylic acid, guanylic acid, and cytidylic acid are present in both DNA and RNA. But uridylic acid is present only in RNA. Instead, in DNA thymidylic acid is present. Another name of thymine is 5-methyl uracil and 2,4 dioxy uridylate is also known as uracil.