So that's the nucleotide. Then we move on to the type of linkage that exists between the sugar and the phosphate groups. And then we move on to the number of phosphate groups that we have. So if we have a single phosphate group that's monophosphate. If we have two phosphate groups that's diphosphate three phosphate groups, as in this case, that's triphosphate. So let's take a look at the ATP molecule.