Solved: The two strands of the helix-shaped DNA molecule are held together by

QUESTION:

The two strands of the helix-shaped DNA molecule are held together by electrostatic forces as shown in Figure 16–44. Assume that the net average charge (due to electron sharing) indicated on H and N atoms is 0.2e and on the indicated C and O atoms is 0.4e. Assume also that atoms on each molecule are separated by 1.0 × 10–10 m. Estimate the net force between (a) a thymine and an adenine; and (b) a cytosine and a guanine. For each bond (red dots) consider only the three atoms in a line (two atoms on one molecule, one atom on the other), (c) Estimate the total force for a DNA molecule containing 105 pairs of such molecules.