Water (H2O):Water is a common example of an amphiprotic substance. It can donate a hydrogen ion to become OH- or accept one to become H3O+.
Zwitterion: This is a molecule that contains both positive and negative charges, but is overall neutral. Like our versatile soccer player, it has the ability to react in different ways under different conditions.
Buffer Solution:A solution that resists changes in pH when small amounts of an acid or base are added. These often contain amphiprotic substances which help maintain this balance.