The two strands of `DNA` are not identical, but are complementary'. Explain this statement.

Explanation

The two strands in DNA molecules are held together by hydrogen bonds between puine base of one strand and pyrimidine base of the other and vice versa. Because of different sizes and geometries of the bases, the only possible pairing in DNA are G(guanine) and C (cytosine) through three H-bonds, (i.e, `C = G`) and between A (adenine) and T (thiamine) through two H-bonds (i.e., `A = T`). Due to this base-pairing principle, the sequence of bases in one strand automatically fixes the sequence of bases in the other strand. Thus, the two strands are complimentary and not identical