Testing and Thinking1.Thehormoneglucagon（胰高血糖素）stimulatesthebreakdownofstoredglycogen（糖原）in liverandmuscle cells by thefollowingenzymes.Whichisthefirstenzymethatmustbeactivated?(a.ProteinkinaseAb.Phosphorylasekinasec.Glycogenphosphorylased.Protein phosphatasee.Proteinphosphataseinhibitor-l2.Fillinthe blankswiththe appropriateterms:(a)is an intracellular proteinthat binds calciumand activatesenzymes.(b)Asubstancethatfitsintoa specificbinding site onthesurfaceof aproteinmoleculeiscalleda
1 Testing and Thinking 1. The hormone glucagon（胰高血糖素） stimulates the breakdown of stored glycogen（糖原） in liver and muscle cells by the following enzymes. Which is the first enzyme that must be activated? ( ) a. Protein kinase A b. Phosphorylase kinase c. Glycogen phosphorylase d. Protein phosphatase e. Protein phosphatase inhibitor-1 2. Fill in the blanks with the appropriate terms: (a) is an intracellular protein that binds calcium and activates enzymes. (b) A substance that fits into a specific binding site on the surface of a protein molecule is called a
Testing and ThinkingCompare and contrast the extracellular matrix(ECM) of animal cells with the walls aroundplant cells.(a)What basic organizational principle underliesboth ECM and cell walls?(b) What are the chemical constituents in each case?(c) What functional roles do the ECM and cell wallshare in common?(d) What functional roles are unique to the ECM? Tothe cell wall?2
2 Testing and Thinking Compare and contrast the extracellular matrix (ECM) of animal cells with the walls around plant cells. (a)What basic organizational principle underlies both ECM and cell walls? (b) What are the chemical constituents in each case? (c) What functional roles do the ECM and cell wall share in common? (d) What functional roles are unique to the ECM? To the cell wall?
Answer(a) Both the ECM of animalcells and the walls around plant cells consist oflong,rigid fibers embedded in an amorphous(无定形的),hydratedmatrix of branched-chain molecules, either glycoproteins (ECM) orpolysaccharides (cellwall)ForECM, thefibers consistof collagen and the matrixis a network of(b)proteoglycans(蛋白多糖).Forcellwalls,thefibersconsistofcellulose纤维素and the matrix is a network of polysaccharides and proteins.Both ECMand cell walls areimportantinmaintainingcell shapeand inretainingwater,therebyresistingcompression.Roles unique to the ECMincluderegulation of cellularprocesses such(d)as adhesion,motility,and differentiation during embryonic development.Roles unigueto cell walls include protection of the cell frommechanicalinjury and microbialinvasion,as well asprovision of themechanicalsupportnecessaryto withstand the turgor pressure that gives planttissues their rigidity.细胞（组织）的膨胀，肿胀3
3 Answer (a) Both the ECM of animal cells and the walls around plant cells consist of long, rigid fibers embedded in an amorphous(无定形的), hydrated matrix of branched- chain molecules, either glycoproteins (ECM) or polysaccharides (cell wall). (b) For ECM, the fibers consist of collagen and the matrix is a network of proteoglycans(蛋白多糖). For cell walls, the fibers consist of cellulose纤 维素and the matrix is a network of polysaccharides and proteins. (c) Both ECM and cell walls are important in maintaining cell shape and in retaining water, thereby resisting compression. (d) Roles unique to the ECM include regulation of cellular processes such as adhesion, motility, and differentiation during embryonic development. Roles unique to cell walls include protection of the cell from mechanical injury and microbial invasion, as well as provision of the mechanical support necessary to withstand the turgor pressure that gives plant tissues their rigidity. 细胞(组织)的膨胀, 肿胀
一、判断题：判断以下各题正确的标T错误的标E锚定蛋白是通过蛋自的氨基酸残基同膜脂的脂肪酸链形成共价键而锚定在质膜上。2.胶原和弹性蛋白都能赋细胞外基质以强度和弹性3.RGD序列是纤粘连蛋白的独特结构，功能是负责同细胞表面结合4细胞间隙连接的连接单位叫连接子，由六个亚基组成，中间有孔道，可以进行物质的自由交换5.整合素是一种受体蛋自，参与内吞作用,并与细胞外基质相连。1.答：F，有两种情况，另一种情况是通过糖与脂的共价连接进行锚定2.答：E胶原赋予强度和韧性，弹性蛋白赋予弹性3.答：F.其他一些蛋白也有RGD序列结构4.答：F不能进行自由交换，要受到连接子孔径的限制5.答：F不参与内吞作用：
4 1. 锚定蛋白是通过蛋白的氨基酸残基同膜脂的脂肪酸链形成共价键而锚定 在质膜上。 2. 胶原和弹性蛋白都能赋予细胞外基质以强度和弹性。 3. RGD序列是纤粘连蛋白的独特结构,功能是负责同细胞表面结合。 4. 细胞间隙连接的连接单位叫连接子, 由六个亚基组成, 中间有孔道,可以 进行物质的自由交换。 5. 整合素是一种受体蛋白,参与内吞作用,并与细胞外基质相连。 一、判断题：判断以下各题,正确的标T, 错误的标F。 1. 答: F, 有两种情况,另一种情况是通过糖与脂的共价连接进行锚定； 2. 答: F, 胶原赋予强度和韧性, 弹性蛋白赋予弹性； 3. 答:F, 其他一些蛋白也有RGD序列结构； 4. 答: F, 不能进行自由交换,要受到连接子孔径的限制； 5. 答: F 不参与内吞作用；
6.蛋白聚糖是在粗面内质网中装配的7.纤维粘连蛋白以不溶的方式存在于细胞外基质，以可溶的方式存在于血浆8.胶原在内质网中是可溶的，在细胞外被基质中是不可溶的。9.选择蛋白和免疫球蛋白超家族蛋白介导的细胞粘着都是钙依赖性的。6.答：T；7.答：T；8.答T;9.答：F，选择蛋白介导的细胞粘着是钙依赖性的，而免疫球蛋白超家族蛋白介导的细胞粘着是非钙依赖性的。5
5 6. 蛋白聚糖是在粗面内质网中装配的。 7. 纤维粘连蛋白以不溶的方式存在于细胞外基质, 以可溶的方式存在于血浆。 8. 胶原在内质网中是可溶的, 在细胞外被基质中是不可溶的。 9. 选择蛋白和免疫球蛋白超家族蛋白介导的细胞粘着都是钙依赖性的。 6. 答: T； 7. 答: T； 8. 答 T； 9. 答: F，选择蛋白介导的细胞粘着是钙依赖性的, 而免疫球蛋白超家族蛋白介导的细 胞粘着是非钙依赖性的