This drawing illustrates a short piece of the DNA helix and illustrates that it contains two strands . The two strands are kept together by the base pairs.

It is a three dimensional structure and in reality the two strands form a spiral structure that resembles a spiral staircase. The DNA molecule is also called a double helix.

The next drawing illistrates this.

The two strings curve around each other to form a sprial structure or a double helix.

The next drawing gives a schematic view of the structure of the double helix. It illustrates that the back bone of the strings consist of phosphate (P) and sugars (S). The sugar is deoxyribose. ( The ordinary sugar we all know is cane sugar and constist of two glucose molecules)

This drawing illustrates how the base pairs keep the two strings together. The two string only seperates during RNA formation and during duplication when the cell prepairs for division.