Protobiogenesis is used for the theory of biochemical origin of life. Protobiogenesis is the term which refers to the process by which living organisms developed from inanimate matter, which is generally thought to have occurred on earth between 3500 and 4000 million years ago. It is supposed that all the primordial atmosphere was like a chemical soup containing all the basic constituents of organic matter like ammonia, CH4,H2, water vapour etc. These underwent a process of chemical evolution using energy from the sun and lightening in the sky.