What Does Oparin's theory Mean
We explain what Oparin's Theory about the origin of life is and his criticisms about it. Also, how is the scheme of this theory.
What is the Oparin Theory?
The Oparin Theory is known as the explanation proposed by the Soviet biochemist Aleksandr Ivanovich Oparin (1894-1980) to answer the question about the origin of life , once the theory of spontaneous generation had been completely rejected .
Oparin proposed that life would have appeared gradually from the emergence of complex substances on the early Earth , from inanimate matter (abiogenesis).
This theory was presented in 1922 to the Moscow botanical society, and although it initially received strong criticism and discredit, it was later experimentally corroborated. As a result, in 1970 Oparin was elected president of the International Society for the Study of the Origins of Life.
Oparin's Theory took advantage of the scientist's knowledge in astronomy , from which he knew that the atmospheres of other planets and stars exist substances such as ammonia, methane and hydrogen, which serve as a substrate to obtain nitrogen, carbon and hydrogen respectively: materials that Together with the oxygen in the water and the atmosphere, they would have served as raw material for life.
This, according to Oparin, would have occurred thanks to the heat of the early Earth and to ultraviolet radiation or electrical discharges from the atmosphere , which provided the necessary energy to start the molecular reactions that would lead to amino acids, peptide bonds and eventually to proteins, suspended in colloids on the planet's surface. The coacervates , later called probionts , would have arisen there .
From the coacervate to the cell
Continuing with the Oparin Theory, the coacervates would have been stable globules of proteins held together by electrostatic forces, which tended to self-synthesize in a medium rich in proteins, sugars and nucleic acids.
Some of these proteins would have acted as enzymes , catalyzing (accelerating or promoting) the synthesis of new macromolecules of nucleoproteins, precursors of the genetic material that we know today.
The coacervates, then, would have enveloped these nucleoproteins and would have formed structures around them, until eventually certain lipids formed small lipoprotein membranes. Thus would have been born the first protocell, the first and most rudimentary forms of life on the planet.
Competition and natural selection would have begun to operate among these primitive cells , pushing them towards an evolutionary race that would engender all forms of life known to date, in a long and complex process of change and adaptation to environmental conditions.
Oparin's Theory can be summarized in the following scheme:
- Abiogenic synthesis. Formation of the first organic compounds from inorganic matter .
- Polymerization. Formation of long chains of complex macromolecules under the action of various energy sources , thus achieving complex compounds essential for life: proteins, polysaccharides and nucleic acids.
- Coacervation. Formation of coacervates, that is, of microscopic aggregates of proteins and polymers separated from the environment by a protomembrane. They are not living beings , but they are the immediately previous step.
- Origin of the primitive cell. The incorporation of nucleic acids into the coacervates allowed inheritance and therefore natural selection, properly giving rise to life in the form of the first autotrophic cells.
See also: Animal cell