Fredagskollokvium: The Astro-Chemical connection: How complex biological molecules are made from small molecules like H2, CO, CO2, NH3 and H2O

Einar Uggerud, Professor, Seksjon for fysikalsk kjemi og Senter for teoretisk og beregningsbasert kjemi (CTCC) Kjemisk institutt Universitetet i Oslo

The hypothesis that animate matter originates from inanimate matter through a spontaneous and gradual increase in molecular complexity was first clearly formulated in 1924 by Alexander Oparin, and is referred to as chemical evolution. The underlying so-called chemical continuity principle states that there is a gradual increase in complexity during this part of evolution.  The process started already when atoms combined to form small inorganic and organic molecules that in turn formed larger organic molecules, and ultimately life.

Prebiotic organic compounds on the early Earth can be divided into two groups depending on whether they were of terrestrial or extra-terrestrial origin. Terrestrial sources include endogenous organic synthesis driven by different energy sources (UV radiation, electric discharge, hydrothermal energy) and has been subject to laboratory simulations. Extra-terrestrial sources of organic material include cosmic dust, meteorites and comets, and are subject to direct examination because these objects continue to deliver organic molecules to Earth. More than 180 small organic molecules have been identified in interstellar space, and biological and organic molecules are found in meteorites and comets (ref. the Rosetta mission).

In our laboratory we study chemical reactivity, including the dissociation and formation of organic molecules. In this respect, we find it rewarding to apply the principle of microscopic reversibility. Studying the spontaneous dissociation of a complex molecule into smaller fragments upon collisional activation has turned out to be a rewarding strategy in identifying how the large molecule can be synthesized from the same small molecule fragments—a direct and naïve application of retrosynthetic analysis, the planning tool of modern organic synthesis.

Besides laboratory studies of reactions in the gas phase, in which we apply various spectroscopic and mass spectrometric methods, we complement our studies with computational quantum chemistry modelling of the reactions, including computer simulations of the reaction dynamics. This will be demonstrated by some examples, including recent studies of amino acids and sugars.

Publisert 1. sep. 2014 21:50 - Sist endret 17. jan. 2015 10:50