1. Draw a structural diagram of the oligodeoxynucleotide 5'-dC-dG-dT-3', both before and after loss of the G due to spontaneous depurination. Show the sugar-phosphate backbone, but don't worry if you can't remember the positions of the amino and keto groups in the C, G and T bases. Indicate the positions of those groups if you can, but otherwise simply show the skeleton of the pyrimidine or purine base, as appropriate. (7 points)
Most students answered this question correctly, but some students need to improve their understanding of and ability to work with DNA structure.
2. What is the name of the site in the oligodeoxynucleotide of question 1 from which the G has been lost? (1 point)
Any of three different names can be used for such a site: apurinic, abasic or AP.
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