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

JEE Advanced · 2024 · 26 May 2024 · Paper 2 · Biomolecules

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 ____

kcal mol^{- 1}

.
[Given : Average energy per H-bond for A-T base pair

= 1.0 kcal mol^{- 1}

, G-C base pair

= 1.5 kcal mol^{- 1}

, and A-U base pair

= 1.25 kcal mol^{- 1}

. Ignore electrostatic repulsion between the phosphate groups.]

Answer: 41

From the given DNA strand, count the base pairs:

Counting from the sequence:

Total H-bonds in A-T pairs =

7 \times 2 = 14

Total H-bonds in G-C pairs =

6 \times 3 = 18

Energy required for A-T pairs =

14 \times 1.0 = 14

kcal/mol
Energy required for G-C pairs =

18 \times 1.5 = 27

kcal/mol

Total energy =

14 + 27 = 41

kcal/mol

JEE Advanced · 2024 · 26 May 2024 · Paper 2 · Integer answer