Figure 33.11 A skeletal representation of the double helix illustrates the helix properties. (A) Side view. Adjacent bases are separated by 3.4 Å. The structure repeats along the helical axis (vertical) at intervals of 34 Å, which corresponds to 10 nucleotides on each strand. (B) End (axial) view, looking down the helix axis reveals a rotation of about 36° per base and shows that the bases are stacked one on top of another.