In which environment would glycine function as a buffer?

Glycine, as a zwitterionic amino acid, can act as a buffer in both acidic and basic conditions. This is due to its unique structure, which contains both an amino group (–NH3⁺) and a carboxyl group (–COO⁻).

In acidic environments, the carboxyl group can donate a proton (H⁺), while in basic environments, the amino group can accept a proton. This dual capability allows glycine to help maintain the pH within a specific range by either neutralizing excess acids or bases. This property is crucial in physiological systems where pH stability is essential for biochemical reactions.

Therefore, the correct answer reflects that glycine can buffer changes in pH effectively across a range of both acidic and basic conditions, making it a versatile buffering agent.