And as we'll see in our discussion on the double stranded helix structure of DNA molecules, these phosphate groups actually are found on the surface of that double helix because they are able to interact with the hydrophilic water molecules. So once again, this means that in an aqueous environment, these hydrophilic regions, these hydrophilic phosphate groups will interact with the polar water molecules to stabilize the structure of DNA. Now, that's not the only thing that these phosphate groups actually do. What they also do is they actually increase the resistance of the DNA molecules to hydrolysis. So remember, anytime we have an Esther Bond, that Esther bond can undergo the process of hydrolysis in which a nuclearphile essentially attacks that bond and breaks that bond. But in this particular case, because we have negative charges on these phosphate groups, these negative charges will repel the negative charge found on the nucleophile.