In the structure of a nucleotide, the phosphate group is attached to which carbon of the sugar (in $5'$)?

What are the properties of the two strands of a double-stranded $DNA$ molecule?

$A$: In a $DNA$ molecule,the proportion of purine and pyrimidine bases is equal.
$R$: In $DNA$,two purines or two pyrimidines do not pair opposite each other.

In sea urchin $DNA$,which is double stranded,$17\%$ of the bases were shown to be cytosine. The percentages of the other three bases expected to be present in this $DNA$ are

In one complete turn of $B-DNA,$ how many purine $N_2$-bases are present?

Which molecule contains the coded information required to produce the chemicals necessary for the organism to function like its parents?