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]
Gene regulation is import4t.ie pzipkyei1 f il3w.5 33eanxm, g +nn+bf m2*b,hbkt for cell differentiation and the development of an organism. For example, the hg,, mbkb++2n*mx nf bdevelopmental pattern of a common fruit fly (Drosophila melanogaster).
Which of the following play a direct role in regulating gene expression?
I. Enhancer
II. Repressor
III. Epigenetic modifications
A. I only
B. II only
C. II and III only
D. I, II and III
参考答案: D
本题详细解析:
Enhancers and repressors bind to specific base sequences of DNA to regulate transcription and, therefore, gene expression. Epigenetic modifications are, notably DNA methylation and histone modification act as a layer of control, turning genes on or off in response to various internal and external signals, thereby determining which genes are expressed and to what extent. Choices A, B and C are incorrect as they do not include all three.
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