Free Radicals

Free radicals are atoms with an unpaired electrons.  Free iron, radiation, drugs  tobacco smoking, gases and other elements can create free radicals usually in the mitochondria.  Free radicals are a leading cause for cell injury in organisms.  Free radicals are harmful if generated in excess or if the antioxidant defense is injured.  Free radicals then take electrons from other atoms to make itself stable, leaving the victim cell a free radicals too.  This chain won't end unless antioxidants come to stabilize the radicals.