If the nucleotides we used were ribonucleotides, the resulting molecule is ribonucleic acid, or RNA. If instead we used deoxyribonucleotides, then we just cooked up DNA. Molecular biologists utilize a simple shorthand to demonstrate this process, as shown in Figure 6.

Figure 6. Formation of Nucleic Acids from Nucleotide Triphosphates. Animation. New nucleotides are added by a reaction between the 3'OH at the end of the growing daughter strand and the triphosphate of an incoming nucleotide, splitting out biphosphate in the process. The new nucleotide always contains a base complementary to the next base on the parent strand. The reaction is catalyzed by an enzyme, DNA polymerase (not shown).