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19. The integrity of the genetic code relies on high-fidelity DNA replication, in which information in a template strand of DNA is transferred to the newly synthesized daughter strand (with A opposite T, and G opposite C). In class, we discussed the results of an experiment in which an unnatural thymine isostere called difluorotoluene (dF; structure shown below) was incorporated as one of the bases in a template strand of DNA. Researchers then used the Klenow fragment of DNA Polymerase 1 (Kf to synthesize a daughter strand of DNA based on this dF-containing template. They observed that as Kf synthesized the daughter strand, it almost exclusively incorporated A in the position opposite dF. This was a surprising result because previous experiments had shown that a DNA duplex containing a "matched" dF-A F base pair is not substantially more stable a DNA duplex containing a mismatched dinuorotoluene (dF) dF-G, dF-C, or dF-T base pair. Which of the following conclusions is consistent with these observations: The ability of Kf to correctly synthesize a daughter strand of DNA that is complementary to the template strand depends primarily on: A. complementary hydrogen bonding between bases B. complementary size and shape of the bases C. the increased electronegativity of fluorine relative to oxygen D. the presence of a C-glycosidic bond in dF instead of an N-glycosidic bond in T

Answer 1

Ans= A

The synthesis of daughter strand of DNA that is complementary to the template strand depends primarily on :

Complementary hydrogen bonding between the bases.