Testing and Thinkingl. Compare 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?()Whatfunctionalroles do the ECM and cell wallsharein common?(d) What functional roles are unigue to the ECM? Tothe cell wall?
1 Testing and Thinking 1. 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?
Question1. How might a liposome be prepared that could potentiallybe used in the treatment of a tumor whose cells have a proteincalled tumor cell antigen (TAG) in their membranes?2.Definediffusion. Include in your answer the thermodynamic driving forcefordiffusionand theenergyrequirement.3.Which of the situations shown below (A or B)will resultin a higherrate ofmovement ofthepositively charged solute acrossthe membraneand in which direction (circleA or B and draw an arrowto indicate thedirection ofmovement)?OUTSIDE++membraneINSIDEAB
2 Question 1. How might a liposome be prepared that could potentially be used in the treatment of a tumor whose cells have a protein called tumor cell antigen (TAG) in their membranes? 2. Define diffusion. Include in your answer the thermodynamic driving force for diffusion and the energy requirement. 3. Which of the situations shown below (A or B) will result in a higher rate of movement of the positively charged solute across the membrane and in which direction (circle A or B and draw an arrow to indicate the direction of movement)?
Answers:1.Make an antibody that recognizes the TAG protein and insert it into aliposomemembrane. Fill theinterior of the liposome with a chemical thatis toxic tothe cell. These liposomes should attach totumor cells and beinternalized after which the toxic chemicals should killthetumor cells2.Diffusion is the spontaneous movement of substances from high tolowconcentration, driven by entropy, no energy required.3.A has highest rate of movementA, from outside to inB, from inside to out3
3 Answers: 1. Make an antibody that recognizes the TAG protein and insert it into a liposome membrane. Fill the interior of the liposome with a chemical that is toxic to the cell. These liposomes should attach to tumor cells and be internalized after which the toxic chemicals should kill the tumor cells. 2. Diffusion is the spontaneous movement of substances from high to low concentration, driven by entropy, no energy required. 3. A has highest rate of movement A, from outside to in B, from inside to out
三、整联蛋白与ECM相互关系Integrins（整联蛋白、整合素）是大多数基质蛋白如胶原、纤连蛋白、层粘连蛋白等的受体。整联蛋白与ECM的结合是受体与配体的结合关系。整联蛋白为一大类跨膜糖蛋白，外连ECM（或细胞）内连细胞骨架，因而是ECM和细胞骨架之间的跨膜桥梁
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()整联蛋白的分子结构基质结合域α、β亚基，跨膜，异二聚体，β链细胞外是球形的头部，露出脂二价阳离子双分子层约20nm。头部可同细胞外半胱氨酸a链基质蛋白结合，富集区S细胞内的尾部同肌动蛋白相连质膜COOHHOOC胞质溶胶踝蛋白和a辅肌蛋白结合区10nm
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