11级制药作业-第5章.docVIP

目录 5.1 Bio-membranes: Lipid Composition and Structural Organization 3 5.1生物膜的脂质成分和组织结构 3 5.2 Biomembranes: Protein Components and Basic Functions 3 5.2 生物膜蛋白组成和基本功能 3 5.3 Organelles of the Eukaryotic Cell 3 5.3 细胞器的真核细胞 3 5.4 The Cytoskeleton: Components and Structural Functions 3 5.4 细胞骨架:组件和结构功能 3 5.5 Purification of Cells and Their Parts 3 5.5 净化细胞和它们的部分 3 5.6 Visualizing Cell Architecture 3 5.6 节中的关键概念 3 Atomic force microscopy reveals sphyingomyelin rafts (orange)protruding from a dioleoylphosphatidylcholine background(black) in a mica-supported lipid bilayer. Placental alkalinephosphatase (yellow peaks), a glycosylphosphatidylinositol-anchored protein, is shown to be almost exclusively raftassociated. [From D. E. Saslowsky et al., 2002, J. Biol. Chem.277:26966–26970.] 原子力显微镜揭示了脂筏（橙色）从L-α-二油酸磷脂酰胆碱背景（黑色）,突出在云母支持的脂质双分子层。胎盘碱性磷酸酶（黄峰），糖基磷脂酰肌醇锚定蛋白，被证明是几乎只筏相关。 Prokaryotes, which represent the simplest and smallestcells, about 1–2 m in length, are surrounded by aplasma membrane but contain no internal membrane-limited sub-compartments (see Figure 1-2a).Although DNA isconcentrated in the center of these unicellular organisms, mostenzymes and metabolites are thought to diffuse freely withinthe single internal aqueous compartment.Certain metabolicreactions, including protein synthesis and anaerobic glycolysis,take place there; others, such as the replication of DNA andthe production of ATP, take place at the plasma membrane.In the larger cells of eukaryotes, however, the rates ofchemical reactions would be limited by the diffusion of smallmolecules if a cell were not partitioned into smaller sub -compartments termed organelles. Each organelle is surroundedby one or more biomembranes, and each type of organellecontains a unique complement of proteins—some embeddedin its membrane(s), others in its aqueous interior space, orlumen. These proteins enable each organelle to carry out itscharacteristic cellular functions. The cytoplasm is the partof the cell outside t