Assertion : The sugar phosphatebackone of two chains in DNA double helix show anti-parallel polarity.
Reason : The phosphodiester bonds in one strand go from a 3' cardon of one nucleotide to a 5, carbon of adjacent nucleotide, whereas those in complementary strand go vice versa.

Options

A. If both assertion and reason are true and reason is the correct explanation of assertion
B. If both assertion and reason are true but reason is not the correct explanation of assertion
C. If assertion is true but reason is false
D. if both assertion and reason are false.

Answer

a

Explanation

The back bone of a DNA chain or strand is built up of alternate deoxyribose sugar and phosphate groups The phosphate group is connected to carbon 5' of the sugar residue of its own nucleoide and carbon 3' of the sugar residue of the next nucleotide by (3' `to` 5') phosphiodister bonds.The two DNA chains are antiparallel , that is , they run prallel but in opposite directions In one chain the direction . In one chain the direction is 5' `to` 3' , while in opposite one , it is 3' `to` 5'