Molecular Biology of the Gene 7th Edition by Richard Losick, James Watson, Michael Levine, Tamara Baker, Alexander Gann

Exercise 5

Structural analogs of nucleosides vary slightly in the chemical structure compared to the primary four nucleosides found in DNA. The structures of two nucleoside analogs used in DNA synthesis experiments are shown below.
A. On the lines labeled 1 and 2, name the dexoynucleoside that these structures mimic.

B. Circle the chemical group(s) on each analog that differs from the conventional deoxynucleoside.