Although oxygen is absolutely essential to metabolism, it can play a role in damaging cells
Highly reactive molecules can oxidize molecules that were previously stable, and may cause them to become unstable species.
Free radicals contain atoms with one or more unpaired electrons. It is an atom or molecule that has an uneven number of electrons.
Atoms and molecules with a neutral charge are chemically stable. A free radical is unstable and tends toward stabilization by pairing the electron; this can destabilize a neighboring molecule through the removal of one of its electrons. This sets up chain reaction as each seceding molecule is made reactive and then seeks to stabilize itself.
During these reactions, free radical oxidative damage can destroy cells. The basic process may be compared to the damage done to food as it becomes rancid.
Oxidation and Free Radical Damage
