Question

For a double strand DNA, one strand is given below:

The amount of energy required to split the double strand DNA into two single strands is _____ \(\mathrm{kcal\ mol^{-1}}\).

[Given: Average energy per H-bond for A-T base pair = \(1.0\ \mathrm{kcal\ mol^{-1}}\), G-C base pair = \(1.5\ \mathrm{kcal\ mol^{-1}}\), and A-U base pair = \(1.25\ \mathrm{kcal\ mol^{-1}}\). Ignore electrostatic repulsion between the phosphate groups.]

Answer 1

Correct answer: 41

Total energy = [BE H-bond A – T \(\times\) No. of A = T pair \(\times\) 2 ] + [BE H-bond G – C \(\times\) No. of G \(\equiv\) C pair \(\times\) 3]

\(= [1 \times 7 \times 2] + [1.5 \times 6 \times 3]\)

\(= 14 + 27\)

\(= 41\) kcal