DNA as a command book of life in the cell, is very important to regulate all processes during the cell. Protecting this life material is one of the most important missions that life has.

Phosphates and sugars of adjacent nucleotides link to form a long polymer. … 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.

This twisted ladder structure helps DNA to be more protected against environmental agents in the cell.