Many eukaryotes have a DNA glycosylase that specifically removes T residues from DNA when paired with G. Why is it better to repair the G-T pairing to G-C by removing the T than to remove the G and form an A-T pair?
A. G-C pairs can form three hydrogen bonds between them and are therefore stronger.
B. Oxidative damage to guanine by alkylation is the most common reason for G-T pairs, so removal of the T will maintain the original G-C pair.
C. T bases easily tautomerize into C bases, so removing the T will make sure the pair stays in its original form.
D. G-C basepairs occur more frequently in cells.
E. All of the choices provided are potential reasons.
B
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A. tympanic membrane ® malleus ®incus ® stapes ® oval window ® cochlea B. tympanic membrane ® incus ®malleus ® stapes ® oval window ® cochlea C. tympanic membrane ® stapes ®malleus ® incus ® oval window ® cochlea D. tympanic membrane ® malleus ®incus ® stapes ® cochlea ®oval window E. tympanic membrane ® oval window ® malleus ®incus ® stapes ® cochlea
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A) additivity B) codominance C) complete dominance D) recessive epistasis E) recessive lethal
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