What does the carboxyl functional group do?

The carboxyl functional group, which is represented as -COOH, is characterized by its ability to donate a proton (H+) to a solution, making it act as an acid. This property is due to the polar nature of the O-H bond within the carboxyl group, which facilitates the release of the hydrogen ion when in an aqueous environment.

In biological systems, the acidity of carboxyl groups is significant because it can influence the structure and reactivity of organic compounds, such as amino acids and fatty acids. When carboxyl groups release protons, they can also contribute to the overall charge of a molecule, impacting its solubility and interaction with other biological macromolecules. This acid-base behavior is central to the role that carboxylic acids play in metabolic pathways and the physiological processes in living organisms.