What is a zwitterion?

A zwitterion is defined as a molecule that has both a positive and a negative charge but is overall neutral. This occurs in certain compounds, particularly amino acids, where one functional group carries a positive charge (typically an ammonium group) and another group carries a negative charge (often a carboxylate group). As a result, the molecule exhibits no net charge, which is a characteristic feature of zwitterions.

The presence of both charges allows zwitterions to take part in unique properties related to solubility and interaction with biological systems. For example, zwitterions can play critical roles in the structure and function of proteins and other biomolecules. This dual-charge state is an important factor in understanding their behavior in various chemical environments, including pH changes and solvent interactions.