I am confused about the structure of nucleotide of a DNA. I have seen that it has a phosphate group(PO₄³⁻) in some books but phosphoric acid(H₃PO₄) in other ones. Which one is right?
The phosphate ion has a negative formal charge and in an acidic solution its appears as a conjugate base of a phosphoric acid. That is the wey the phosphate group found in cells. The nucleotide synthesis can occur de novo or recovery ways. De novo way use phosphoribosyl pyrophosphate, which simple molecules such as amino acid, tetrahydrofolate and carbon dioxide are added.