Explanation

DNA is a polymer of nucleotides, which comprise nitrogen base (A, G, T, C), sugar (deoxyribose) and phosphoric acid. The four types of nucleotides present in DNA are as follows: [table] Deoxynu-cleoside | $+ H_{3}PO_{4}$ | Deoxyribonu-cleotide | Abbre-vation ; Deoxyad-enosine | $+ H_{3}PO_{4}$ | Deoxyadenylic acid | $d$AMP ; Deoxygu-anosine | $+ H_{3}PO_{4}$ | Deoxyguanylic acid | $d$GMP ; Deoxycyt-idine | $+ H_{3}PO_{4}$ | Deoxycytidylic acid | $d$CMP ; Deoxythy-midine | $+ H_{3}PO_{4}$ | Deoxythymidylic acid | $d$TMP [/table]