Homochirality of Organic Matter – Objective Law or Curious Incident?

2018

Symmetry

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The discovery of meteoritic alpha-amino acids with significant enantiomeric excesses of the L-form has suggested that some cosmic factors could serve as the initial source for chiral imbalance of organic compounds delivered to the early Earth. The paper reviews major hypothesis considering the influence of chiral irradiation and chiral combinations of physical fields on the possible ways asymmetric synthesis and transformations of organics could take place within the solar system. They could result in a small enantiomeric imbalance of some groups of compounds. More attention is paid to the hypothesis on parity violation of weak interaction that was supposed to cause homochirality of all primary particles and a more significant homochirality of compounds directly synthesized from the latter in a plasma reactor. The first experiment with material synthesized in a plasma torch resulting from a super-high-velocity impact showed formation of alanine with the excess of L-form between 7 and 25%. The supposed conclusion is that L-amino acids could serve as a starting homochiral biomolecular pool for life to emerge all over the Universe.

Section: Parity Violation In the Weak Interaction And Homochirality Omentioning

confidence: 99%

Biological Homochirality on the Earth, or in the Universe? A Selective Review

2018

Symmetry

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“…The latter was shown to predominantly destroy one of the two enantiomers of racemic amino acids such that the last traces of the product achieve some optical activity (of no more than a few percent) [73]. As summarized in detailed reviews by Barron et al [74] and Davankov [66,75], similar small effects of deracemization of synthetic amino acids were also observed on the action of spin-polarized electrons emitted by the β-decay of radioactive nucleons, of polarized beams of electrons, as well as due to the influence of a strong magnetic field (e.g., of a nascent neutron star from a core-collapsed supernova). Importantly, the supernova-derived neutrino irradiation is also expected to result in a small chiral imbalance of the same sign of chirality for all different amino acids [76].…”

Section: Origins Of Biological Homochiralitymentioning

confidence: 99%

“…For a protein world, Davankov [65,66] tried to estimate the probability of an accidental emergence of a peptide composed of 100 amino acid units. There exist many dozens of alpha-amino acids.…”

Section: Origins Of Biological Homochiralitymentioning

confidence: 99%

Chance and Necessity in the Evolution of Matter to Life: A Comprehensive Hypothesis

2021

Symmetry

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Specialists in several branches of life sciences are trying to solve, piece by piece, the immensely complex puzzle of the origin of life. Some parts of the puzzle seem to appear with a rather high degree of clarity, while others remain totally obscure. We cannot be sure that life emerged only on our Earth, but we believe that the presence of large amounts of water in its liquid state is absolutely essential for the emergence and evolution of living matter. We can also assume that the latter exploits everywhere the same light elements, mainly C, H, O, N, S, and P, and somehow manipulates the same simple monomeric and polymeric organic compounds, such as alpha-amino acids, carbohydrates, nucleic bases, and surface-active carboxylic acids. The author contributes to the field by stating that all fundamental particles of our matter are “homochiral” and predominantly produce in an absolute asymmetric synthesis amino acids of L-configuration and carbohydrates of D-series. Another important point is that free atmospheric oxygen mainly stems from the photolysis of water molecules by cosmic irradiation and is not necessarily bound to living organisms on the planet.

“…PRIMARY ATMOSPHERE The Big Bang, which is estimated to have occurred 13.8 billion years ago, should have produced identical numbers of high-energy photons, baryons, and antibaryons. According to the latest concepts, baryons and antibaryons are not only particles and antiparticles, but also pairs of steric enantiomers [3][4][5]. They quicky annihilated one another (i.e., turned into photons).…”

Section: Origin and Evolution Of The Earth'smentioning

confidence: 99%

“…They formed in large quantities from carbon-containing inorganic matter during the collision of different space objects with ultra-high speeds [16]. An important additional incentive for the origin of life must have been the recently hypothesized and experimentally confirmed direct synthesis from elements, which leads to the predominant formation of amino acids of precisely the L-configuration needed for life [4,5,17].…”

Section: Photosynthesis As a Source Of Oxygen And Organic Mattermentioning

confidence: 99%

The Riddle of Atmospheric Oxygen: Photosynthesis or Photolysis?

2021

Russ. J. Phys. Chem.

The stoichiometry of the photosynthetic reaction requires that the quantities of the end products (organic biomaterial and free oxygen) be equal. However, the correct balance of the amounts of oxygen and organic matter that could have been produced by green plants on the land and in the ocean since the emergence of unique oxygenic photosynthetic systems (no more than 2.7 billion years ago) is virtually impossible, since the vast majority of oxygen was lost in oxidizing the initially reducing matter of the planet, and the bulk of organic carbon is scattered in sedimentary rocks. In recent decades, convincing information has been obtained in favor of the large-scale photolysis of water molecules in the upper atmosphere with the scattering of light hydrogen into space and the retention of heavier oxygen by gravity. This process has been operating continuously since the formation of the Earth. It is accompanied by huge losses of water and the oxidation of salts of ferrous iron and sulfide sulfur in the oceans and methane in the atmosphere. The main stages of the evolution of the atmosphere and surface layers of the Earth’s crust are analyzed for the first time in this work by considering the parallel processes of photosynthesis and photolysis. Large-scale photolysis of water also provides consistent explanations for the main stages in the evolution of the nearest planets of our Solar System.