What is the formula for a phosphate group?

The formula for a phosphate group is represented as PO4. This indicates that the group consists of one phosphorus atom (P) surrounded by four oxygen atoms (O). In biochemical contexts, phosphate groups are crucial components of nucleotides, which make up DNA and RNA, as well as ATP (adenosine triphosphate), the energy currency of the cell.

Phosphate groups can exist in various forms, typically with one or more negative charges due to the presence of ionizable protons in acidic conditions. This ability to donate and accept protons plays a significant role in biological processes, such as energy transfer and signal transduction.

The other choices represent different chemical groups: CO3 is the carbonate ion, SO4 is the sulfate ion, and N2H4 is hydrazine. None of these structures contain phosphorus nor serve the same biological roles as phosphate groups, further affirming that PO4 is indeed the correct representation of a phosphate group.