CHED 1720 |
| A reservoir of organic compounds, supplied by either endogenous or exogenous sources, is thought to be necessary for the origin of life. It has been demonstrated that the action of an electric discharge on reduced gas mixtures such as H2O, CH4 and NH3 (or N2) results in the production of copious amounts of several biologically important organic compounds such as amino acids. However, it is now widely held that the early Earth's atmosphere was likely neutral, dominated by N2 and CO2. The synthesis of organic compounds by the action of electric discharges on neutral gas mixtures has been shown to be much less efficient. However, we show here that contrary to previous findings, significant amounts of amino acids are produced under these conditions. The low yields found previously were the result of oxidation of the organic compounds during hydrolytic workup by nitrite and nitrate produced in the reactions. Addition of oxidation inhibitors prior to hydrolysis results in the recovery of several hundred times more amino acids than reported previously. Organic synthesis from neutral atmospheres may thus have depended as much on oceanic conditions as on the characteristics of the primitive atmosphere itself. These findings imply the need for a critical re-evaluation of the importance of such syntheses on the primitive Earth and other planetary bodies, such as Mars, that may have been endowed with CO2 and N2-rich atmospheres throughout a major part of their history. |
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Chemical Evolution, Chemical Change Across Space and Time
1:30 PM-4:30 PM, Wednesday, March 28, 2007 McCormick Place North -- Room N227A, Level 2, Oral
Division of Chemical Education |