Electrostatic forces play an important role in biological systems, as many macromolecules, like DNA, are heavily charged $($see Example $13).$ In fact, the electrostatic attractive force holds the two strands of DNA together, giving the molecule its strength and the famous structure of its double helix $($see the image$).$ The four organic bases of DNA $($cytosine $[$C$],$ guanine $[$G$],$ adenine $[$A$],$ and thymine $[$T$])$ hold the two strands together by forming pairs of bases that bond through these electrostatic forces. The order of the bases varies along the strand, but the pairing between bases is always the same; C always pairs with G$,$ and A always pairs with T$.$ In order for the pairs of bases to bond, they must be sufficiently close together. A guanine and cytosine, for example $($see the image$),$ pair by forming three hydrogen bonds $($noncovalent bonds$)$ between oxygen and nitrogen atoms. While a single hydrogen bond is relatively weak, the large number of them between complementary pairs gives the DNA molecule its strength. Calculate the electrostatic force of attraction within one hydrogen bond. Model the bond as a simple electric dipole, where equal and opposite charges of $(+/$e$)$ are separated by a distance of $0\mathrm{.}30$ nm$.$