Miller–Urey Experiment: Results, Conclusion, and Definition
Miller Urey Experiment
At the time of 1950s in America, there was much speculation about outer space travel. The president of Unites States at that time named Dwight D. Eisenhower send a satellite in orbit in 1957-1958, known as International Geophysical Year.
But unfortunately, in a demonstration of cold war rivalry, the Soviet Union was the first to launch Sputnik, again on the ground, American researchers, undergone a set of experiments to understand a possibility of life in extraterrestrials, and the origin of life on earth.
Thus, the elegant and famous set of observation was Miller Urey experiment, which was undergone by a graduate student Stanley Miller and a Biochemist Harold. C. Urey at Chicago University in the year 1953.
The success of their spawned the scientific subspecialty of exobiology. Exobiology is nothing but a speculative study of life forms beyond the earth.
Purpose of Miller Urey Experiment
When Miller and Urey began their research to understand about the origins of life on earth, they first observed themselves, that they knowledge on two things first the history of earth including the chemical components present in the atmosphere, the amount of sunlight, and water and then about the chemical properties between the living materials.
However, Oparin gave the basis of their ideas about the primordial earth. Miller has also said in an experiment that earth has a status of reducing atmosphere, as all of the outer planets that is present in our solar system such as Jupiter, Saturn, Uranus and Neptune which are all similar as of Earth in their atmospheres.
The discovery of double helical structure of the DNA by Watson and Crick helped Miller and Urey understand about the chemical nature of the Living material.
Where the Watson and Crick discovered the DNA, which is made up of a sequence of nucleic acids which codes for specific amino acids, which is considered as the building blocks of proteins.
From this Miller and Urey concluded that life begin at a minimum amino acids present.
What was Miller Urey Experiment?
The Miller Urey experiment was the first attempt to explore the ideas scientifically based on the origin of life.
The main concept of this experiment is to test the idea of a complex molecules of life which arises on our younger planets through simple and natural chemical reactions.
The building blocks of life have been characterized in the early 19th century. Depending on how the molecules are produced, prime interests to the origin of life are considered.
Two major achievements are given, the one is in the year 1850, where Adolf Strecker succeeded as the first in synthesizing the amino acid in a laboratory as amino acid alanine from a mixture of acetaldehyde, ammonia and hydrogen cyanide.
After few years, in 1861, Alexandr Butlerov, attempted and succeeded in first laboratory synthesis of mixture of sugar from alkaline catalyst.
Even these discoveries were considered as interesting and an appreciable one, they are not related to life problems.
Hence progressing a little improvement in a scientific description, the origin of life was introduced by Ivanovich Oparin.
As Oparin introduced the concept of chemical evolution, which can be seen in Darwin theory of evolution, this concept related to life stood as successive result of spontaneous chemical reaction which produce increasing complex structure of chemicals.
He suggested that such chemical evolution takes place only within an oxidizing atmosphere of the early earth.
Then further, he made modification in his early suggestions and concluded that early atmosphere to a high reducing environment.
As such similar ideas were proposed by English biologist John Haldane who mentioned Prebiotic soup, where the evolution of chemicals takes place.
Oparin and Harold ideas were expressed the experiments in a theoretical level only the conformation for this experiments were given by Miller and Harold Clayton Urey who conceived and built an experiment to stimulate a putative Primitive earth environment.
The Real Miller Urey Experiment
In this experiment a gaseous mixture of hydrogen, methane, ammonia and water were exposed to electrical discharge which stimulates a storm of lightening.
Then this mixture was connected to a bulb which was filled with liquid water that can be heated.
Then it was observed ed that 15 percentage of carbon present in the mixture present as methane was converted into simper carbon components such as formaldehyde and hydrogen cyanide.
These compounds are then combined to a simple form of molecules such as formic acid and urea and some other complex molecules that contains carbon-carbon bonds including those of amino acids, alanine and glycine.
As a result of these processes, the end product was large number of organic molecules containing several amino acids.
Hence these experiments became s experiments proof for the theory of chemical evolution and it has also shown us the chemistry between simple molecules, which are found abundant in the atmosphere primitive to the earth and which leads to the synthesis of vital components which leads to the formation of earth.
Miller Urey Experiment is Not Conclusive
This experiment was a great achievement as they showed the primitive and important biotic components which are abiotically synthesized in the environment and stimulating natural conditions.
But it is not yet been concluded and still many researches are under progress as there are several findings which proves that this experiment is wrong.
Miller Urey Experiment Citations
- From Anodic Oxidation of Aliphatic α-Amino Acids to Polypeptides by Quantum Electrochemistry Approach: Beyond Miller Urey Experiments. J Am Chem Soc . 2019 Sep 11;141(36):14230-14238.
- Conducting miller urey experiments. J Vis Exp . 2014 Jan 21;(83):e51039.
- Theory of chemical evolution of molecule compositions in the universe, in the Miller Urey experiment and the mass distribution of interstellar and intergalactic molecules. J Theor Biol . 2020 Feb 7;486:110097.
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