SUMMARY: If you beam water and pyrimidines at low temperature and pressure in a sealed chamber, you’ll produce pyrimidine-based molecules such as uracil, cytosine, isomers of uracil and cytosine. You’ll also get urea and glycine. As samples warm up, the amount of products change as they react with each other. Tables and figures in this article talk about the various types of pyrimidine-based products and the conclusion talks about the significance of these products. Water’s role was very important. It’s important to note that at low temperatures (15-40K), all the molecules are basically solids (hence the ice references).
LESSON COMMENTS: In biology, the only pyrimidines students know of are the ones found in DNA. This article shows students all the different types of pyrimidine-based molecules that are out there and their significance.
The tools used to identify products can be discussed both in chemistry and physics class: Infrared spectroscopy, high performance liquid chromatography, gas chromatography mass spectrometry. Students can see how chromatography is used outside of crime scene/evidence analysis of ink.
Nuevo, M., Milam, S. N., & Sandford, S. A. (2012). Nucleobases and Prebiotic Molecules in Organic Residues Produced from the Ultraviolet Photo-Irradiation of Pyrimidine in NH3 and H2O NH3 Ices. Astrobiology,12(4), 295-314. doi:10.1089/ast.2011.0726