本题目来源于试卷: Continuity and Change D.4 Cell & Nuclear Division，类别为 IB生物学
[单选题]
Which of the following starx4ormp ;m) vusejg m +h-a(* +q*7dki)dd wc(tements does not describe awwuc rq4y*azb0q85jt : c /a3h step in the sodium-potassiurz4/ju *wwqhc 0c:b qa3y85atm pump cycle in the neuronal cells?
A. Three sodium ions attach to their binding sites in the pump from the interior of the cell.
B. The pump changes shape upon being phosphorylated, and sodium ions are released to the outside.
C. Three potassium ions attach to their binding sites in the pump from the exterior of the cell.
D. The pump changes shape upon releasing the phosphate group, and potassium ions are released to the interior of the cell.
参考答案: C
本题详细解析:
Two potassium ions, not three, are transported in the sodium-potassium pump cycle. The sodium-potassium pump cycle is as follows: three sodium ions attach to their binding sites (Choice A), the pump changes shape to release the sodium ions to the exterior of the cell (Choice B) and finally, the pump changes shape again to release two potassium ions to the interior of the cell (Choice D).
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