What structural features of the DNA molecule ensure the performance of its functions?

A DNA molecule is made up of two long chains of polynucleotides, which are made up of four types of nucleotide subunits. Each such strand is known as a DNA strand. Together, the two chains are held together by hydrogen bonds. The nucleotides are covalently linked by a chain through sugars and phosphates, which thus form the “backbone” of an alternating sugar-phosphate-sugar-phosphate. The elements of each base pair can be combined in a double helix only if the two strands of the helix are antiparallel.