本题目来源于试卷: Continuity and Change D.5 Gene Expression，类别为 IB生物学
[单选题]
The rate mRNA is degraded in the cytoplasm is sometimes reducei-f0u, qnh7 y5 m *j8zs(*c4jlnepbued in response) l6ii3 qsaz;i to environmental stimuli. How might this mechanism of producing more polypeptides for a given gene increase an individual's fiiil) a3;sq z6itness?
A. Greater number of polypeptides increases fitness
B. Polypeptide degradation decreases
C. Rate of mRNA synthesis increases
D. Quantity of ATP used per polypeptide synthesised decreases
参考答案: D
本题详细解析:
Choice D is correct because if mRNA persists in the cytoplasm for a longer period of time, less mRNA needs to be synthesised per polypeptide synthesised. mRNA synthesis requires ATP so a reduced need to synthesise mRNA conserves energy which may enhance the organism's chances of reproductive success. Choice A is incorrect because a greater number of polypeptides does not necessarily increase fitness. Choice B is incorrect because a reduced rate of mRNA degradation does not affect the rate polypeptides are degraded. Choice C is incorrect because if mRNA persists in the cytoplasm for longer periods of time, less mRNA needs to be synthesised to replace degraded mRNA.
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