环境化学10.pdf

第十一章 生物体内污染物质的 运动过程及毒性 Chap 11 The transformation and toxicity of pollutants in organisms 主要内容 第一节 物质通过生物膜的方式 Unit 1 How substances get through Biological Membrane 第二节 污染物质在机体内的转运 Unit 2 The transport of pollutants inside bodies 第三节 污染物质的生物富集、放大和积累 Unit 3 Bio-concentration, bio-magnification and Bioaccumulation, 第四节 污染物质的生物转化 Unit 4 Biotransformation of Polluted Ma 第五节 毒作用的生物机制 Unit 5 Types of Biotransformation of Toxic Organic Pollutant 第一节 物质通过生物膜的方式 Unit 1 How substances get through Biological Membrane 一、生物膜的结构 Constitution of Biological Membrane 二、物质通过生物膜的方式 Pathways for pollutants enter into membrane 一、生物膜的结构 Constitution of Biological Membrane A biological membrane or biomembrane is an enclosing or separating amphipathic layer that acts as a barrier within or around a cell. – 是环绕细胞和各种独特的亚细胞（如核、线粒体、 溶酶 体等）的区室的界面 – 起着选择性通透屏障的作用，使得细胞或细胞器的内环境 不同于外环境 – 参与信号传递过程 • Such membranes typically define enclosed spaces or compartments in which cells may maintain a chemical or biochemical environment that differs from the outside. For example, the membrane around peroxisomes shields the rest of the cell from peroxides, and the plasma membrane separates a cell from its surrounding medium. Most organelles are defined by such membranes, and are called membrane-bound organelles. • Probably the most important feature of a biomembrane is that it is a selectively-permeable structure. This means that the size, charge, and other chemical properties of the atoms and molecules attempting to cross it will determine whether they succeed to do so. Selective permeability is essential for effective separation of a cell or organelle from its surroundings. Biological membranes also have certain mechanical or elastic properties. • If