The experiments of Miller and Fox and their significance

The experiments of Miller and Fox and their significance

The experiment of Stanley Miller was most significant as it provides a conclusive evidence for the chemical synthesis of life. The experiment conducted by Miller in the year 1953 consisted of a spe­cifically prepared flask in which was kept a mixture of gases, methane, ammonia and Hydrogen.

The flask was sealed after sterilization. A high frequency electric spark was discharged in a constantly circulating man­ner so that it keeps continuous contact with the gases. In order to provide water vapour a small quantity of water was boiled and supplied through a tube to the mixture. In short, the entire environment was simulated as it must have existed on the nascent earth.

After about a week, the analysis of the mixture in the flask (which was in the form of a solution due to the condensation of water vapour) was analysed as to its chemical constituents. It showed that the mixture had amminoacids like gylcine, alanine, aspartic acid, glutamic acid etc., In addition to this, many aldehydes and HCN were also present.

Subsequent experiments by many scientists clearly showed that amino acids can be synthesised by inorganic compounds. On the primitive earth with a reducing atmosphere moderate energy sources were sufficient to pro­duce major groups of organic compounds necessary for living systems on earth.

Under the influence of reducing atmosphere dilute alkaline aque­ous systems can produce amino acids, sugars, fatty acids, purines, pep­tides and polypeptides. The energy for the formation of these organic compounds must have come from ultra violet radiation, intermittent light­ning and ionizing radiations etc.

The experiment of Stanley Miller shows that organic compounds can come from inorganic compounds. But the question is how these organic com­pounds have reached the stage of the first life form even though there are several theories which try to explain this stage many doubts also have been expressed regarding these theories. It has to be accepted that origin of life is still an open question. Some of the more important theories are those of Oparin and S.W. Fox.

Fox’s theory: S.W. Fox in his experiments simulated the conditions of volcanic eruptions that he belived were existing on the primitive earth. In these experiments he showed the polymerisation of aminoacids into mol­ecules called proteinoids as they were unlike true proteins.

These proteinoids group together and form what are known as microspheres. These proteinoid microspheres according to Fox can metabolize glucose. Thus according to Fox and Oparin the microspheres and coecervates are the first structures that constituted the ancestry of all living beings. It is these that subsequently gave rise to the first life forms.