问题 单项选择题

在呼吸链中,既可作为NADH脱氢酶受氢体,又可作为琥珀酸脱氢酶受氢体的是

A.FAD
B.铁硫蛋白
C.Cytb
D.CoQ

答案

参考答案:D

解析:生物体内存在两条氧化呼吸链,即NADH氧化呼吸链和琥珀酸氧化呼吸链。
NADH氧化呼吸链:NADH→FMN(Fe-S)→CoQ→Cytb→4Cytc1→Cytc→Cytaa3→O2
琥珀酸氧化呼吸链:琥珀酸→FAD→CoQ→Cytb→Cytc1→Cytc→Cytaa3→O2
可见CoQ是两条呼吸链的交会点,因此CoQ既可作为NADH脱氢酶受氢体,又可作为琥珀酸脱氢酶受氢体。

完形填空

第二节:完形填空(共20小题;每小题1. 5,满分30分)

阅读下面短文,从短文后各题所给的四个选项(A、B、C和D)中,选出可以填入空白的最佳选项,并在答题卡上将该项涂黑。

Facial expressions carry meanings, which depends on situations and relationships. For instance, in American culture the smile is typically an expression of    36   .Yet it has other functions. A smile may    37    love, politeness, or    38   true feeling. It is also a source of confusion across    39   .    40   , many people in Russia    41   smiling at strangers in public to be unusual or even suspicious. Yet many Americans    42    freely at strangers in public places. Some Russians believe that Americans smile in the wrong    43   ; some Americans believe that Russians don't smile enough. In Southeast Asian cultures, a smile is frequently used to cover emotional pain or mental difficulty, discomfort or anxiety.

Our faces make our emotions and attitudes known,    44    we should not try to "read" people from another culture    45    we would "read" someone from our own culture. The degree of facial expressiveness one shows changes    46   persons and cultures. The fact that members of one culture do not   47    their emotions as openly as members of    48    does not mean    49   they do not    50    emotions. Rather, their cultures    51    them expressing their emotion and attitudes freely.

If we    52    people whose    53    of showing emotion are not the same according to  54   own cultural patterns, we may make the    55    of "reading" the other persons incorrectly.

36. A. worried                            B. surprise                    C. excitement                D. pleasure

37. A. show                         B. tell                          C. sound                       D. seem

38. A. cover                         B. cultures                    C. include                     D. suggest

39. A. countries                    B. cultures                    C. nations                     D. oceans

40. A. In a word                   B. As a result                C. For example             D. On the contrary

41. A. keep                          B. enjoy                       C. continue                   D. consider

42. A. stare                          B. smile                       C. look                         D. shout

43. A. direction                    B. manner                    C. time                         D. place

44. A. and                           B. so                            C. but                          D. or

45. A. as                              B. though                            C. unless                      D. since

46. A. among                       B. into                         C. between                   D. about

47. A. find                           B. form                        C. express                     D. control

48. A. the others                   B. others                      C. the other                  D. another

49. A. whether                            B. that                          C. if                             D. why

50. A. experience                 B. use                          C. bring                       D. carry

51. A. feel                           B. keep                        C. prevent                    D. make

52. A. think                         B. observe                    C. judge                       D. watch

53. A. hopes                        B. ways                        C. thoughts                   D. means

54. A. your                          B. their                        C. one's                        D. our

55. A. answer                       B. mistake                    C. promise                    D. use

问答题 简答题