问题 填空题

下表是8种生物细胞色素c与人的细胞色素c的组成比较,请分析表中数据后回答:(已知细胞色素c由104个氨基酸组成)

生物名称
黑猩猩
猕猴
金枪鱼
小麦
链孢霉
酵母菌
与人的细胞色素c有差异的氨基酸数为
0
1
12
13
21
35
43
44

(1)从表中数据可发现生物的细胞色素c的氨基酸组成和生物的亲缘关系是:亲缘关系越近,细胞色素c的氨基酸组成差异________。(2)从表中看,人和_________的亲缘关系最远,因为二者的________________________________。 (3)上述对生物细胞色素c的氨基酸的组成比较,是从_____________方面为生物的__________提供了证据。

答案

(1)越小

(2)酵母菌 细胞色素c的氨基酸组成差异最大

(3)分子生物学 进化理论

选择题
阅读理解

七选五(每小题2分, 满分10分) 根据短文内容, 从短文后的选项中选出能填入空白处的最佳选项, 并在答题卡上将该项涂黑。选项中有两项为多余选项。

  When a starving man gets a meal,  he begins to think about an overcoat; when an executive(业务主管)gets a new sports car, visions of country clubs dance into view. The many wants of mankind might be regarded as making up several levels.    2 .The first and most basic levels of wants involve food. Once this want is satisfied, a second level of wants appears: clothing and some sort of shelter. By the end of World War II these wants were satisfied for a great majority of Americans.    3   It included such items as automobiles and new houses. By 1957 or 1958 this third level of wants was fairly well satisfied. Then, in the late 1950s a fourth level of wants appeared: the “life-enriching” level. While the other levels involve physical satisfaction-the feeding, comfort, safety, and transportation of the human body-this level stresses mental needs for recognition, achievement and happiness. It includes a variety of goods and services, many of which could be called “luxury”(奢侈) items. Among them are vacation trips, the best medical care, and entertainment.  4     On this level, a greater percentage of consumer spending goes to services, while on the first three levels more is spent on goods. Will consumers raise their sights to a fifth level of wants as their income increases, or will they continue to demand luxuries and personal services on the fourth level? A fifth level probably would involve wants that can be achieved best by community action. Consumers may be spending more on taxes to pay for government action against disease, ignorance, crime and prejudice.   5  In this way, we can enjoy more fully the good things on the first four levels.

A.Then a third level appeared.

B.Human wants seem endless.

C.When there is money enough to satisfy one level of wants, another level appears.

D.There are several levels of wants in one’s life.E.At this stage, we now may seek to ensure the health, safety, and leisure.

F.Also included here are fancy foods and the latest styles in clothing.

G.Different people have different wants on each level.