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.]
$\begin{matrix}
\underset{X}{\mathop{H}}{{O}_{2}}C-C{{H}_{2}}-CH-C{{O}_{2}}\underset{Z}{\mathop{H}}\, \\
\,\,\,\,\,\,\,\,\,\,\,| \\
\,\,\,\,\,\,\,\,\,\,\,\,\,+N{{H}_{3}} \\
\end{matrix}$
The isoelectric point for the amino acid is