Write the characteristic features of DNA.

Explanation

Features of DNA: (i) If one strand runs in the 5.-3. direction, the other runs in 3-5. direction and thus are antiparallel (they run in opposite direction). The 5. end has the phosphate group and 3. end has the OH group
(ii) The angle at which the two sugars protrude from the base pairs is about `120^(@)`, for the narrow angle and `240^(@)` for the wide angle. The narrow angle between the sugars generate a minor groove and the large angle on the other edge generates major groove.
(iii) Each base is 0.34 nm apart and a complete turn of the helix comprises 3.4 nm or 10 basepairs per turn in the predominant B form of DNA.
(iv) DNA helical structure has a diameter of 204 and a pitch of about 34A. X-ray crystal study of DNA takes a stack of about 10 bp to go completely around the helix `(360^(@))`
.(v) Thermodynamic stability of the helix and specificity of base pairing hydrogen bonds between the complementary bases of the double ases of the double helix (ii) stacking interaction between bases tend to stack about each other perpendicular pendicular to the direction of helical axis. Electron cloud interactions (II - II) between the bases in(II - II) between the bases in the helical stacks contribute to the stability of the double helix.
(vi) The phosphodiester linkages gives an inherent polarity to the DNA helix.1ney tomu covalent bonds, gives the strength and stability to the polynucleotide chain.