What is the major role of the phosphate buffer system?

The major role of the phosphate buffer system is to help maintain the pH balance in biological systems. It consists of a mixture of dihydrogen phosphate (H2PO4-) and hydrogen phosphate (HPO4^2-) ions, which can act as either a weak acid or a weak base to buffer changes in pH by accepting or donating protons. This system is important for maintaining the acid-base equilibrium in cells and bodily fluids.