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 more stable than another (4-ef s)fqr;msne qd9 DNA87n) gcvz:hqv 4a.qch 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 molecule i m;;e//crw, k+bcl qvss 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 (St/+ ebw vsqc kl,m;/;rcatement I) means a greater number of hydrogen bonds (Statement II).Choice A is incorrect 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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