62. Give an account of the Miller and Urey experiment on the origin of life.

Harold C. Urey, an astronomer provided the first adequate recognition to Oparin Haldane’s view, on the origin of life in 1952.

Miller made the first successful simulation experiment to assess the validity of the claim for origin of organic molecules in the primitive earth condition. Miller designed the apparatus of glass tubes and flasks and created an atmosphere containing hydrogen, ammonia, methane and water vapour in one chamber of the apparatus and allowed condensed liquids to accumulate in another chamber. Energy was supplied by heating the liquid containing chamber as well as by electric sparks from electrodes in the gaseous chamber.

The experiment was run continuously for a week and then they analysed the chemical composition of the liquid inside the apparatus. They found that the liquid contained a large number of complex organic compounds including some amino-acids such as glycine, alanine and aspartic acid. Since then the experiment was repeated many times and scientists have recovered most amino-acids that are present in protein molecules as well, as adenine and other nucleic acid bases. However, from the result of their experiment, they suggested that the electrical discharges produced dunng lightening in the primitive atmosphere of earth containing hydrogen, ammonia, nitrogen and water vapour might have resulted in the formation of amino-acids and other essential building blocks of ‘living organisms’ could, thus have formed on the primitive earth.

The conclusion drawn by the experiment of Miller and Urey provides support for the biochemical concept of origin of life of Oparin and Haldane.