This preview shows page 1. Sign up to view the full content.
Unformatted text preview: CHEMISTRY Departmental Seminar Dr. Stefanie Milam NASA Ames Research Center Ultraviolet Irradiation of Pyrimidine in Interstellar Ice Analogs: Formation and Stability of Nucleobases Recent studies have verified the presence of amino acids in organic residues formed by the UV photolysis of ~10 K ices representative of interstellar and cometary environments (H 2 O, CO, CO 2 , CH 3 OH, NH 3 , etc.) [1-3]. These results suggest that molecules of prebiotic interest could potentially form in space and are further supported by the detection of amino acids in meteorites [4-6]. Nucleobases, the informational units of RNA and DNA, have also been detected in specific types of meteorites, known as carbonaceous chondrites [7,8], and constitute another family of prebiotic compounds that can possibly form in interstellar environments. These molecules are functionalized nitrogenous polycyclic aromatic species (PANHs). There are two classes of nucleobases: pyrimidines (e.g. thymine, uracil, and cytosine) and purines (e.g. adenine and guanine). The functionalization of (e....
View Full Document