Identify the nitrogen atom of a purine base that bonds with the $1^{\prime}$ carbon of ribose to form a ribonucleoside.

Which of the following bases is bicyclic?

Which of the following is a purine derivative?

The average energy of each hydrogen bond in $A-T$ pair is $x \, kcal \, mol^{-1}$ and that in $G-C$ pair is $y \, kcal \, mol^{-1}$. Assuming that no other interaction exists between the nucleotides,the approximate energy required in $kcal \, mol^{-1}$ to split the following double stranded $DNA$ into two single strands is:
$A$-$T$-$A$-$T$-$G$-$C$-$A$-$G$
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$T$-$A$-$T$-$A$-$C$-$G$-$T$-$C$

The segment of $DNA$ which acts as the instrumental manual for the synthesis of the protein is

$A$ nucleic acid,whether $DNA$ or $RNA$,gives on complete hydrolysis,two purine bases,two pyrimidine bases,a pentose sugar,and phosphoric acid. Nucleotides,which are intermediate products in the hydrolysis,contain: