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Hypotheses and dilemmas around the origin and uniqueness of life

100%

Legocki A. B.

Nauka

2020

nr 3

The emergence of life on Earth and its almost infinite diversity, reflected by a myriad of living organisms, are among the dilemmas that have forever fascinated scientists and philosophers. Today, we are still not able to determine what exactly initiated the chain of events leading to the rise of life – the mechanism of replication of initial structures or perhaps the occurrence of first metabolic reactions. Further approximations of these issues shall probably constitute an overwhelming driving force for future development of life sciences.

Heterogeneous radiolysis of urea. Implications in astrobiology and prebiotic chemistry

80%

Abigail E. Cruz-Hernández, A. E. , Colin-Garcia M. , Heredia-Barbero A. , Negron-Mendoza A. , Ramos-Bernal S.

Open Chemistry

2015

tom 13

nr 1

Urea is an organic molecule present in most living organisms. Historically, it was the first organic molecule synthesized in the laboratory. In prebiotic chemistry, urea readily forms in different laboratory simulations using different energy sources. Furthermore, the role of solid surfaces, particularly minerals, might have been crucial to increase the complexity of the organic matter which may have led to the subsequent emergence of life on Earth. In this work, the radiolysis of urea in presence of a clay is studied to determine to what extent the mineral surfaces influence the decomposition of organics. The results indicate that urea is relatively stable to ionizing radiation in aqueous solutions and up to 20 kGy no decomposition is observed. Moreover, the presence of sodium montmorillonite, by a mechanism until now unknown, affects the radiolytic behavior and urea remains in the heterogeneous solution without a change in concentration even at very high doses (140 kGy). These results indicate that solids could have protected some organics, like urea, from degradation enabling them to remain in the environment on the primitive Earth.

Hypotheses and dilemmas around the origin and uniqueness of life

80%

Legocki A. B. , Legocki A. B.

Nauka

2020

nr 3