linguistic:voice_change
Oxidative challenge in biology

Reactive oxygen species produced in cells include hydrogen peroxide (H O), hypochlorous acid (HClO), and free radicals such as the hydroxyl radical (·OH), and the superoxide anion (O). The hydroxyl radical is particularly unstable and will react rapidly and non-specifically with most biological molecules. This species is produced from hydrogen peroxide in metal-catalyzed redox reactions such as the Fenton reaction. These oxidants can damage cells by starting chemical chain reactions such as lipid peroxidation, or by oxidizing DNA or proteins. Damage to DNA can cause mutations and possibly cancer, if not reversed by DNA repair mechanisms, while damage to proteins causes enzyme inhibition, denaturation, and protein degradation.