Now, what else can we say about this backbone? So notice that because the backbone contains these repeating phosphate groups and because the phosphate groups carries a negative charge, that makes this part of the backbone hydrophilic. So water loving, that's because we have a dipole moment that exists as a result of the charge that is delocalized among these two oxygen atoms within our phosphate group. So notice that the phosphate group contains a negative charge. And this means two important things. Number one, when we place our DNA or RNA molecule into an aqueous solution, which is a solution found in our cells and inside the nuclei of our cells, the structure of that DNA molecule and RNA molecule will basically exist in such a way as so as to make sure that these phosphate groups actually interact with the polar water molecules.