Cold prebiotic evolution, tunneling, chirality and exobiology
- N.N. Semenov Institute of Chemical Physics Russian Academy of Sciences UL.Kosygina 4, 117334 Moscow (Russia)
The extra-terrestrial scenario of the origin of life suggested by Svante Arrhenius (1) as the {open_quote}panspermia{close_quote} hypothesis was revived by the discovery of a low-temperature quantum limit of a chemical reaction rate caused by the molecular tunneling (2). Entropy factors play no role near absolute zero, and slow molecular tunneling can lead to the exothermic formation of quite complex molecules. Interstellar grains or particles of cometary tails could serve as possible cold seeds of life, with acetic acid, urea and products of their polycondensation as quasi-equilibrium intermediates. Very cold solid environment hinders racemization and stabilizes optical activity under conditions typical for outer space. Neither {open_quote}advantage{close_quote} factors can secure the evolutionary formation of chiral purity of initial prebiotic monomeric medium{emdash}even being temporary achieved it cannot be maintained at subsequent stages of prebiotic evolution because of counteraction of {open_quote}enantioselective pressure{close_quote}. Only bifurcational mechanism of the formation of prebiotic homochiral{emdash}monomeric and afterwards polymeric{emdash}medium and its subsequent transformation in {open_quote}homochiral chemical automata{close_quote} ({open_quote}biological big bang{close_quote}{emdash}passage from {open_quote}stochastic{close_quote} to {open_quote}algorithmic{close_quote} chemistry) is possible and can be realized. Extra-terrestrial (cold, solid phase) scenarios of the origin of life seem to be more promising from that point of view than terrestrial (warm) scenarios. Within a scheme of five main stages of prebiological evolution some problems important for further investigation are briefly discussed. {copyright} {ital 1996 American Institute of Physics.}
- OSTI ID:
- 451114
- Report Number(s):
- CONF-9502169-; ISSN 0094-243X; TRN: 9703M0119
- Journal Information:
- AIP Conference Proceedings, Vol. 379, Issue 1; Conference: Physical origin of homochirality in life, Santa Monica, CA (United States), 15-17 Feb 1995; Other Information: PBD: Jul 1996
- Country of Publication:
- United States
- Language:
- English
Similar Records
Enantiomeric excesses induced in amino acids by ultraviolet circularly polarized light irradiation of extraterrestrial ice analogs: A possible source of asymmetry for prebiotic chemistry
NON-RACEMIC AMINO ACID PRODUCTION BY ULTRAVIOLET IRRADIATION OF ACHIRAL INTERSTELLAR ICE ANALOGS WITH CIRCULARLY POLARIZED LIGHT