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 v z.itavy hj-(w:1 f*pstable than another DNA molem4(1kt2kkee/rr2st f mxajh-5 8g3n qcule?
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 correct3lqs 8xmpmdtc-j gi)u+6 bj 0a +zipqmar3 050 because the stability of the DNA helix molecule 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 incorrect as it3+a368i u-0 c0sl0 qixmp bdagmmq)pjz+r5tj 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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