来自《耶鲁大学开放课程：生物医学工程探索 第7集 第7集》

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  and we're going to come back to that a little bit later in the lecture.
  我们会在稍后讲解这个内容
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  If a cell membrane was indeed just a lipid bilayer,
  如果细胞膜只是一个脂质双分子层的话
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  then glucose could never enter the cell
  葡萄糖就不可能进入细胞
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  because it can't permeate through cell membranes.
  因为它不能渗透过细胞膜
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  Glucose has to get into cells,
  但葡萄糖又必须进入细胞
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  that's the main source of energy source that cells use,
  因为它是细胞能量的主要来源
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  metabolism of glucose.
  即通过葡萄糖代谢产生能量
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  It does so because there are some molecules in
  而这个过程的完成依赖于
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  the surface of the membrane
  膜表面存在的一些分子
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  that allow glucose to move in and out.
  这些分子能够将葡萄糖运进或者运出细胞
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  Those are called glucose transporters.
  这些分子叫做葡萄糖转运载体
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  There's another whole family of molecules that sit in the surface.
  在细胞膜上还存在着另一类分子