Unity and Diversity A.2 Nucleic Acids (id: 68f2e3304)

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]
Which of the labelleq/ b*.+tr2 5ddgvmat2o od/o yd structures shows the correct directionality of the DNAreei. fx5s 9b l+izy9s:(3yhu moleculef3(u+iiy9l9syzs r.h xb:e5e ?

A.
B.
C.
D.


参考答案:  C


本题详细解析:
Choice C is correct rh( fb pwu+t .u0wik f88dn-f9because the left strand is running in the 5’ - 3’ direction with the phosphate group attached to the 5th carbon at the 5’ end, and the 3rd carbon of the terminating deoxyribose sugar is free. The right strand is running antiparallel in the 3’-5’ direction.Choice A is incorrw0+.8-wbi fu8hdrpfk9u ( f tnect because both strands are labelled as running in the 5’ - 3’ direction, and the carbons of the deoxyribose sugars are incorrectly labelled. Choice B is incorrect because the strands are incorrectly labelled with the 5’ and 3’ ends, and the carbons of the deoxyribose sugars are incorrectly labelled on both strands. Choice D is incorrect because both strands are labelled as running in the 3’ - 5’ direction, and the carbons of the deoxyribose sugars on both strands are incorrectly labelled.

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