全国2013年4月自学考试生物化学（三）试题_第4页

26.在正常机体内，两种主要转氨酶(AST和ALT)在何种部位中活性最低?

A.心脏                                                             B.肝脏

C.肾脏                                                             D.胰腺

E.血液

27.下列化合物中不属于核苷酸的是

A.NAD⁺                                                           B.NADP⁺

C.FAD                                                             D.TPP

E.ATP

28.下列化合物中属于体内嘧啶核苷酸补救合成原料的是

A.一碳单位                                                      B.天冬氨酸

C.谷氨酰胺                                                      D.CO₂

E.尿嘧啶

29.下列酶和蛋白因子中参与DNA复制的是

A.RNA聚合酶                                                  B.DNA聚合酶

C.sigma因子                                                    D.Rho因子

E.RF因子

30.一个基因中可转录生成RNA的DNA链是

A.亲代DNA                                                     B.模板链

C.编码链                                                         D.领头链

E.随从链

31.蛋白质翻译延长所需要的酶或因子是

A.解链酶                                                         B.EF

C.IF                                                                 D.Rho因子

E.sigma因子

32.tRNA运载氨基酸时连接氨基酸的键是

A.盐键                                                             B.氢键

C.肽键                                                             D.酯键

E.磷酸二酯键

33.下列不属于酶别构调节特点的是

A.含多个亚基聚合                                           B.有催化和调节亚基

C.代谢物常为别构剂                                        D.别构剂与酶共价结合

E.活性改变时伴有构象变化

34.下列酶中可受茶碱抑制，使cAMP半衰期延长的是

A.腺甘酸环化酶                                               B.鸟苷酸环化酶

C.磷酸二酯酶                                                  D.蛋白激酶A

E.蛋白激酶G

35.细胞外液的主要阳离子和阴离子分别是

A.K⁺和Mg²⁺；Cl^-和HC0₃^-。                              B.Na⁺和K⁺；Cl^-和HCO₃^-

C.K⁺和Mg²⁺；有机和无机磷酸                         D.Na⁺和K⁺；有机和无机磷酸

E.Na⁺和Me²⁺；有机酸和蛋白质