本题目来源于试卷: Unity and Diversity A.2 Nucleic Acids，类别为 IB生物学
[单选题]
What would make one DNA molecule j977au91n(b ywisrfr wzop/ 6mnev4/tj 7fl/ ltuqi 4qi47 fm:ore stable than another DNA molecule?
I. More G-C base pairs than A-T base pairs
II. More hydrogen bonds between base pairs
III. Greater distance between A-T base pairs than G-C base pairs
A. I only
B. III only
C. I and II only
D. I, II and III
参考答案: C
本题详细解析:
Choice C is correct because the stability of the DNA helix moldt2cyee*g2ums d /424elwnj ) ecule is affected by the nucleotide composition. There are 3 hydrogen bonds between the G-C base pairs, and only 2 between the A-T base pairs, therefore, more G-C pairs (Statement I) means a greater number of hydrogen bonds (Statement II).Choice A is incorre42eyd2e)td*u 2/sclmn jgw e4 ct as it does not include both correct statements.The distance between the A-T base pairs and the G-C base pairs is equal, and even if the distance between A-T were greater, it would not add to stability (Statement III). Choices B and D are therefore incorrect as they include Statement III.
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