細(xì)胞生物學(xué)期中試卷(2003-11-22)(編輯修改稿)
2025-02-05 11:09 本頁面
【文章內(nèi)容簡介】 式相作用的小分子的普遍稱呼； d．對于一個(gè)與蛋白質(zhì)以非共價(jià)形式相作用的小分子的普遍稱呼； e．一個(gè)缺乏酶活性的球蛋白 13．膜膽固醇的組成與質(zhì)膜的性質(zhì)、功能有著密切的關(guān)系 ,（ ） a．膽固醇可防止膜磷脂氧化； b．正常細(xì)胞惡變過程中，膽固醇 /磷脂增加； c．膽固醇 /磷脂下降，細(xì)胞電泳遷移率減少； d．在質(zhì)膜相變溫度以下，增加膽固醇，可以提高膜的流動性 14．用抗纖連蛋白的抗體注射胚體，發(fā)現(xiàn)在神經(jīng)系統(tǒng)發(fā)育過程中神經(jīng)嵴細(xì)胞的遷移受到抑制。這些實(shí)驗(yàn)說明： ( ) a．神經(jīng)嵴發(fā)育包括抗體基因的表達(dá)； b．發(fā)育中的神經(jīng)無需合成纖連蛋白； 5 c．纖連蛋白 /抗體復(fù)合物形成神經(jīng)細(xì)胞的遷移途徑； d．胚胎中的神經(jīng)元在移動過程中必須與纖連蛋白暫時(shí)結(jié)合 15．當(dāng)胰島素與其受體酪氨酸激酶結(jié)合后，隨后發(fā)生的事件是 ( )。 a． IRS 的結(jié)合 → 具有 SH2 區(qū)域的蛋白質(zhì) 的磷酸化 → 效應(yīng)； b．與具有 SH2 區(qū)域的蛋白質(zhì)結(jié)合 → IRS 的磷酸化 → 效應(yīng)； c．自磷酸化并將 IRS 磷酸化 → 與具有 SH2 區(qū)域的蛋白質(zhì)結(jié)合 → 效應(yīng)； d．自磷酸化并與 IRS 結(jié)合 → 將具有 SH2 區(qū)域的蛋白質(zhì)磷酸化 → 效應(yīng) 四、簡答題 (每題 4 分，共 40 分 ) 1. What functional roles do the ECM (細(xì)胞外基質(zhì) )and cell wall share in mon? 2. Discuss the following analogy(相似 ): “The differences between transporting a ligand by a channel or a carrier protein are like the differences between crossing a river by a bridge or a ferry(擺渡 ). 3. EGTA chelates(螯合 ) Ca2+ with high affinity and specificity. How would microinjection(微注射 ) of EGTA affect glucagontriggered breakdown of glycogen (糖原 ) in liver? 4. The basic structure of biological membranes is determined by the lipid bilayer, but their specific functions are carried out largely by proteins. Explain your answer. 5. Why does a red blood cell membrane need proteins? 6. Describe the different methods that cells use to restrict proteins to specific regions of the plasma membrane. Is a membrane with many anchored proteins still fluid? 7. Transport by carrier proteins can be either active or passive, whereas transport by channel proteins is always passive. Explain your answer. 8. The signaling mechanisms used by a steroidhormone(固醇激素 ) receptor and by an ionchannellinked receptor have very few ponents(組分 ). Can either mechanism lead to an amplification of the initial signal? If so, how? 9. Should RGS (regulator of G protein signaling) proteins be classified as GEFs (guanine nucleotide exchange factors) or GAPs (GTPase activating proteins)? Explain what role this activity plays in modulating Gproteinmediated responses in animals and yeasts. 10. How is an IP3triggered Ca2+ response terminated? 6 五、簡述第二信使 cAMP 的發(fā)現(xiàn)及生成的實(shí)驗(yàn)證明 (20 分 )。 六、分析與思考 (任選一題 , 20 分 ) 1. Why do you suppose that phosphorylation/dephosphorylation, plays such a prominent role in switching proteins on and off in signaling pathways? 2. The Ras protein functions as a molecular switch that is set to its on state by a guaninenucleotide exchange factor (GEF) that causes it to bind GTP. A GTPaseactivating protein (GAP) resets the switch to the off state by inducing Ras to hydrolyze its bound GTP to GDP much more rapidly than in the absence of the GAP. Thus Ras works like a light s
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