A.I. Oparin

Biografie şi Bibliografie

 -
Alexander Ivanovich Oparin (Russian: Алекса́ндр Ива́нович Опа́рин; in English, Aleksandr Ivanovich Oparin) (March 2 [O.S. February 18] 1894, Uglich, Russia – April 21, 1980, Moscow) was a Soviet biochemist notable for his contributions to the theory of the origin of life, and for his authorship of the book The Origin of Life. He also studied the biochemistry of material processing by plants, and enzyme reactions in plant cells. He showed that many food-production processes are based on biocatalysis and developed the foundations for industrial biochemistry in the USSR.

Life

Oparin graduated from the Moscow State University in 1917 and became a professor of biochemistry there in 1927. Many of his early papers were on plant enzymes and their role in metabolism.[3] In 1924 he put forward a theory of life on Earth developing through gradual chemical evolution of carbon-based molecules in primordial soup. In 1935, he along with academician Alexey Bakh, founded the Biochemistry Institute by the Academy of Sciences of the USSR. In 1939 Oparin became a Corresponding Member of the USSR Academy of Sciences, and in 1946 - a full member of the Academy. In 1940s and 1950s he supported pseudo-scientific theories of Trofim Lysenko and Olga Lepeshinskaya, who made claims about "the origin of cells from noncellular matter", and 'taking the party line' helped his career.[4] In 1970, he was elected President of the International Society for the Study of the Origins of Life. On his passing on April 21, 1980, he was interred in Novodevichy Cemetery in Moscow.

Oparin became Hero of Socialist Labour in 1969, received the Lenin Prize in 1974 and was awarded the Lomonosov Gold Medal in 1979 "for outstanding achievements in biochemistry". He was also awarded five Orders of Lenin.

Theory of the origin of life

Oparin sometimes is called "Charles Darwin" of the 20th century. Although he began by reviewing the various panspermia theories, including those of Hermann von Helmholtz and William Thomson Kelvin, he was primarily interested in how life initially began. As early as 1922, he asserted the following tenets:

1. There is no fundamental difference between a living organism and lifeless matter. The complex combination of manifestations and properties so characteristic of life must have arisen in the process of the evolution of matter.

2. Taking into account the recent discovery of methane in the Celestial body atmospheres of Jupiter and the other giant planets, Oparin postulated that the infant Earth had possessed a strongly reducing atmosphere, containing methane, ammonia, hydrogen, and water vapor. In his opinion, these were the raw materials for the evolution of life.

3. At first there were the simple solutions of organic substances, the behavior of which was governed by the properties of their component atoms and the arrangement of those atoms in the molecular structure. But gradually, as the result of growth and increased complexity of the molecules, new properties have come into being and a new colloidal-chemical order was imposed on the more simple organic chemical relations. These newer properties were determined by the spatial arrangement and mutual relationship of the molecules.

4. In this process biological orderliness already comes into prominence. Competition, speed of cell growth, survival of the fittest struggle for existence and, finally the natural selection determined such a form of material organization which is characteristic of living things of the present time.

Oparin outlined a way in which basic organic chemicals might form into microscopic localized systems possible precursors of the Cell from which primitive living things could develop. He cited the work done by de Jong on coacervates and other experimental studies, including his own, into organic chemicals which, in solution, may spontaneously form droplets and layers. Oparin suggested that different types of coacervates might have formed in the Earth's primordial ocean and been subject to a selection process leading eventually to life.

While Oparin himself was unable to do extensive experiments to investigate any of these ideas, scientists were later able to. In 1953 Stanley Miller performed what is perhaps the first experiment to investigate whether chemical self-organization would have been possible on the early earth. The Miller-Urey experiment showed that from a mixture of several simple components of a reducing atmosphere, with the input only of heat to provide reflux and electrical energy (sparks, to simulate lightning), a variety of familiar organic compounds such as amino acids were synthesised within a fairly short period of time. The compounds that formed were somewhat more complex than the molecules that were present at the beginning of the experiment.

As the molecular structure of DNA and RNA became understood, due to the work of James D. Watson and Francis Crick, the opinion became more widespread among molecular geneticists, that it would take very little time before life could be artificially created: even if it needed to be limited to very simple life forms. They agreed to Oparin's theory.

The influence of dialectical materialism on Oparin's theory

The influence of the Marxist theoretical concept of dialectical materialism, part of the Communist Party's official interpretation of Marxism, fit Oparin's definition of life as 'a flow, an exchange, a dialectical unity'. This notion was enforced by Oparin's association with Lysenko.

Cărti de A.I. Oparin


Cum Cumpăr Cum plătesc Livrare
0 cărţi in coş
Total : 0 RON