In DNA, the 2 strands of nucleotides (deoxyribose) are twisted into a right handed helix, when does it make its complete turn? What is the backbone of these 5' - 3' and 3' - 5' orientated strands?

The 2 strands of nucleotides in DNA are twisted together into a right handed helix, making its complete turn every 10 nucleotides (a distance of roughly 3.4 nm) Its backbone is made up of sugar phosphate, in both 5' - 3' orientated strands, and 3' - 5' orientated strands (which are anti-parallel)