SSC MTS EXAM

Detailed explanation-1: -DNA consists of two strands that wind around each other like a twisted ladder. Each strand has a backbone made of alternating sugar (deoxyribose) and phosphate groups.

Detailed explanation-2: -They showed that alternating deoxyribose and phosphate molecules form the twisted uprights of the DNA ladder. The rungs of the ladder are formed by complementary pairs of nitrogen bases-A always paired with T and G always paired with C.

Detailed explanation-3: -The deoxyribose and the phosphate groups form the backbone of the nucleic acid molecule. Nitrogenous bases, which are bound to the deoxyribose groups, protrude from the backbone. In the double helix, these bases protrude into the centre of the double helix.