细胞质的结构与功能.ppt

1、第五节 细胞质的结构与功能 (二)The Structure and Function of Cell Cytoplasm,1. 细胞的能量转换:线粒体 Energy Conversion: Mitochondria 2. 蛋白质合成装置:核糖体 Protein Synthesis Machine :Ribosome 3. 细胞骨架 The Cytoskeleton,线粒体的结构 Mitochondrial structure,外膜(outer membrane） 内膜（inner membrane） 膜间隙（intermembrane space） 基质（matrix）,Mitochondr

2、ial structure,Outer membrane: Contains channel-forming protein, called Porin. Permeable to all molecules of 5000 daltons or less.,Inner membrane (Impermeability): Contains proteins with three types of functions: (1) Electron-transport chain: Carry out oxidation reactions; (2) ATP synthase: Makes ATP

3、 in the matrix; (3) Transport proteins: Allow the passage of metabolites,Intermembrane space: Contains several enzymes use ATP to phosphorylate other nucleotides.,Matrix: Enzymes; Mit DNA, Ribosomes, etc.,Molecular basis of oxidative phosphorylation,线粒体的结构 Mitochondrial function,电子传递链(Electron-trans

4、port chain),F1 particle is the catalytic subunit; The F0 particle attaches to F1 and is embedded in the inner membrane.,F1: 5 subunits in the ratio 3:3:1:1:1,F0: 1a：2b：12c,ATP合成酶的结构(The structure of the ATP synthase),F1颗粒具有ATP合成酶的活性F1 particles have ATP synthase activity,Proton translocation through

5、 F0 drives ATP synthesis by F1,ATP合成酶是可逆的偶联装置The ATP synthase is a reversible coupling device,化学渗透假说Mithchells Chemiosmotic theory (1961),The pH and electrical gradient resulting from transport of protons links oxidation to phosphorylation; Electrons pass from NADH or FADH2 to O2, the terminal elect

6、ron acceptor, through a chain of carriers in the inner membrane; As electrons move through the electron-transport chain, H+ are pumped out across the inner membrane, and form Proton motive force.,质子动力势Proton motive force,Transport of electrons from NADH,核糖体Ribosome,Ribosomes are about 20nm in diamet

7、er and are composed of 65% ribosomal RNA and 35% ribosomal proteins . Prokaryotes have 70S ribosomes, each consisting of a small (30S) and a large (50S) subunit Eukaryotes have 80S ribosomes, each consisting of a small (40S) and a large (60S) subunit,The structure of ribosome,The activity sites of r

8、ibosome,微管Microtubules 微丝Microfilament 中间纤维Intermediate filaments,细胞骨架 cytoskeleton,细胞骨架的主要功能 Key to Cytoskeleton functions,The intracellular distribution of Microtubules, Microfilaments and intermediate filaments.,微管的结构与组成structure and constitute of microtubules,In cilia and flagella,In centrioles

9、and basal bodies,三类微管存在方式 Three types of structures of microtubules,纤毛与鞭毛的结构Structure of cilia and flagella,微管的动态不稳定性dynamic instability of microtubules,微管的功能The functions of microtubules,1、纺锤体和染色体运动 Mitotic spindle and Chromosome movement 2、维持细胞形态 Maintain the cell shape 3、 细胞内物质的运输 Transport of in

10、tracellular substance 4、特化细胞结构（纤毛、鞭毛）的运动 The movement of cilia and flagella,纺锤体和染色体运动Mitotic spindle and Chromosome movement,细胞内物质的运输Transport of intracellular substance,A general model for kinesin- and dynein-mediated transport in a typical cell,特化细胞结构（纤毛、鞭毛）的运动The movement of cilia and flagella,Mo

11、vement format of flagella and cilia,微丝(microfilament, MF),MF also called actin filaments, which are thin and flexible filaments, approximately 7nm in diameter.,单体肌动蛋白monomeric G-actin,微丝的装配Assembly and structure of actin filaments Structure of an actin monomer,Assembly of actin filaments,微丝的功能Functi

12、on of microfilament,维持细胞形态,赋予质膜强度 Maintain shape of cell, endow plasma membrane with intensity 参与肌肉受缩 Muscle contraction 参与胞质分裂 Participate in plasma division,Maintain shape of cell, endow plasma membrane with intensity,Muscle contraction,Participate in plasma division,中间纤维（intermediate filament,IF)

13、, 10 nm filaments, called intermediates their diameter : between the thin actin- containing filaments and the thicker myosin filaments of smooth muscle cells,Classes of intermediate filaments,Assembly of IF,中间纤维的功能Function of intermediate filament, Increase mechanical strength Forming and maintain of desmosome Structural support for contr