本题目来源于试卷: Interaction & Interdependence C.4 Chemical Signaling，类别为 IB生物学
[单选题]
Which of the following is only i5xz yer):dqou sr(/k.bc8z .able t; au,. hwihbd7,uoo w2wag1:egd(uf;o trigger a response in a cell by binding to a receptor i( e,. , 1ah;gowub;:d72uwfuoa wh igdn the plasma membrane?
A. Insulin
B. Testosterone
C. Oestradiol
D. Progesterone
参考答案: A
本题详细解析:
A Choice A is correct because insulin is a peptide hormone, which is polar so cannot directly pass through the plasma membrane. Instead it binds to receptors in the plasma membrane which triggers intracellular signalling pathways. Choices B, C and D are all incorrect, as they are all non-polar steroids so can diffuse through the plasma membrane and bind directly to receptors inside the cell, affecting gene expression.
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