Free radicals are chemical species that contain a single unpaired electron in an outer orbit. They are molecules with an odd number of electrons that have high instability. They become responsible for the aging and the degeneration of the cells in all species of creation. The molecules are of free radical characters that have a missing or an impaired electron in the outer shell.
There are many kinds of free radicals. To give an example, 15 cc of water or half an ounce has sixty billion trillion molecules in it. A free radical is the size one of such molecules and it lasts only for 0.000000001 second. It fulfills its job of getting an electron to fill its outer shell.
Free radicals can occur in both organic and inorganic molecules. They are quite reactive and their reactions are crucial for normal activity in a large spectrum of biological processes. They are also created in the catalytic action of several cellular enzymes and electron transport processes and are implicated in a series of both physiologic and pathological processes. Organisms can get exposed to free radicals in various ways other than through normal metabolic processes. Additionally, a large variety of environmental agents such as drugs which are capable of redox cycling and xeno-biotics can form free radical metabolites. The process of aging also causes free radical damage to cells.