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| Format: | Artículo científico |
| Sprache: | en |
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Academia Brasileira de Ciências
2000
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| Online-Zugang: | https://www.redalyc.org/articulo.oa?id=32772305 |
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Inhaltsangabe:
- Surface Charges and Interfaces: Implications for mineral roles in prebiotic Chemistry Mila Buarque Pontes Ana C. Tessis José A. P. Bonapace Marisa Monte B. M. Fernando Barros de Souza Adalberto Vieyra Multidisciplinaria (Ciencias Naturales y Exactas) surface reactions mineral interfaces prebiotic reactions There exists an extensive literature on the possible roles of minerals in the prebiotic stages of the chemicalevolution of life (Bernal 1951, Cairns-Smith 1982, Wächtershäuser 1992, Vieyra et al. 1995, Tessis et al.1999, see Lahav (1994) for a review). Among the original proposals, minerals have been considered in: (a)processes thatwould discriminate molecular chirality; (b) condensation reactions of biomolecular precursors;(c) prebiotic catalysis; (d) biochemical templates; and (e) autocatalytic metabolism. In this communication itis emphazised the complex properties of both surface reactions and interfaces between minerals and aqueoussolutions simulating Archean scenarios. The properties of pyrite surface net charge and of its interfacewith a solution simulating primitive seawater are discussed and their implications to the autocatalytic model(Wächtershäuser 1988a 1992) are presented in order to demonstrate their relevance. The proposed roles ofiron-sulfide minerals (mainly pyrite) as physical support for primitive bidimensional metabolism and chiraldiscriminator (Wächtershäuser 1988a, Huber&Wächtershäuser 1998) are revised. It is shown that: (a) the netsurface charge can be modulated by the pyrite-aqueous solution interface; (b) mononucleotides attachmentto pyrite require a cationic bridge; and (c) direct absorption of acetate - a molecule proposed as carbonsource in primitive aqueous environments - also modulates the interface properties and would have maskedpyrites bulk structure. These results indicate that physicochemical changes of mineral surfaces - causedby environments simulating Archean aqueous scenarios - should be taken into account in the proposals ofmineral prebiotic roles. 2000 artículo científico 0001-3765 https://www.redalyc.org/articulo.oa?id=32772305 en http://www.redalyc.org/revista.oa?id=327 Anais da Academia Brasileira de Ciências application/pdf Academia Brasileira de Ciências Anais da Academia Brasileira de Ciências (Brasil) Num.3 Vol.72