  We give unambiguous theoretical analyses and show that the exclusive
biochemical reaction involved in a single nucleotide insertion into the DNA
primer can be efficiently tracked using the renormalized van der Waals (vdW)
interaction of a stronger type, the Hermansson blue-shifting hydrogen bond
effect, and the Arunan composite hydrogen-vdW bond. We find that there are two
biochemical steps involved to complete the insertion of a single base
(cytosine) into the 3$'$ end of a DNA primer. First, the O3$'$ (from a DNA
primer) initiates the nucleophilic attack on P$_{\alpha}$ (from an incoming
dCTP), in response, O3$_{\alpha}$ (bonded to P$_{\alpha}$) interacts with H$'$
(bonded to O3$'$). These interactions are shown to be strongly interdependent
and require the forming and breaking of P---O and H---O covalent bonds, which
in turn imply that we do not need any external energy supply.
