问题 单项选择题

在航天技术日益发展的21世纪,利用太空的特殊环境,制造真正的灵丹妙药以攻克威胁地球人的不治之症,不是无稽之谈.目前激素、酶、抗体类特效药制剂都是通过选用哺乳动物细胞进行培养制取的,而在体外培养大量活细胞难度非常大.要使大量的细胞脱离原体后仍有生命功能,必须使它们依附他物,而且细胞之间互不干扰.没有可依附的物体表面,这些细胞不能存活,便谈不到制取有价值的生物制剂.生物学家通常让“培养细胞”分散依附在直径小于百万分之一英寸的特制塑料小球表面,将小球置于有培养介质液的罐中,使之吸收介质中的营养并进行新陈代谢.但是,在地球重力作用下,小球往往会沉降,依附在球#画上的细胞也会"叠罗汉",下层的细胞在成为饿的过程中产生着毒素,上层的细胞则因为兼容并蓄而前景堪忧.如果在太空中,上述情况便会发生逆转.失重,会使“培养细胞"保持旺盛的活力.失重环境最利于生物物质的分离与提纯.生物学家和医药学家最感兴趣的电泳技术的作用在未来的太空制药厂里可以得到尽如人意的发挥.电泳技术是将质量和电荷的比值不同的粒子在电场中分离的一种方法.利用这种方法既可分离不同组分的混合物,又能分离细胞和蛋白质,甚至从“衰老”的细胞群中分离出“年轻”的细胞.在地面上,所有粒子都会同时受到电场力和重力的作用,电泳操作难度极大.当电力使培养细胞或培养介质受热时,对流和沉淀现象将并发(往往以一种现象为主,如重力大于电场力,沉淀就将起主要作用).对流或沉淀都会使已经分离的组合重新混合.克服此弊,需要创造失重环境.在“阿波罗一联盟”号飞船实验室中进行的电泳分离试验非常成功,从大约5%的肾细胞中分离出尿激素,其分离效率是地面上的6~O倍,而且质量极好.这种在地面上难以提取的尿激素是溶解血栓或凝血的特效药.航天飞机投入使用后,在机内空间实验室中多次进行了电泳试验,成功的从血浆中分离出激素、酶和蛋白质.太空生物制品专家K·威斯指出,在太空实验室利用电泳技术生产血浆蛋白的效率要比地球上高700倍.发展太空制药业或生物制品的前景是非常广阔的.疫苗制品的生产,人体细胞和白蛋白的提纯与制造,血红细胞生成素的配置……都可能成为高科技、高盈利生产项目.有人估计,仅疫苗一项,每年的经济收益将超过15亿美元.更重要的是,地球上数以百万计的“绝症”患者也会因太空的灵丹妙药而起死回生.

下列叙述,不符合文意的一项是______.

A.在地球上无法进行哺乳动物细胞的体外培养,而在太空中能够顺利完成

B.利用太空的特殊环境提取生物制品的科学实验取得进展,研发前景看好

C.在太空实验室利用电泳技术提取生物激素、蛋白质等,效率高、质量好

D.发、展太空制药与生物制品业将会取得良好的社会效益和巨大的经济效益模拟试卷六

答案

参考答案:A

解析:哺乳动物细胞的体外培养在地球上能够进行的,只是难度极大.其他项的叙述在原文都有依据.

阅读理解
阅读理解。
      Jack is six years old. He has no sisters. But he has a brother. His brother's name is Mike. Jack likes
eating apples, oranges and bananas. Sometimes he eats some of his brother's apples. And his brother hits
him for that. He doesn't like Mike. This September he is going to school.
      It's the ninth day at school. Jack and his classmates are having a new lesson.
      "Jack, how much is five minus three, please?"
     "It's…it's…" 
     "Now, listen to me," says the teacher, "If your sister has five apples, and you have eaten three of them…" 
     "But I have no sisters." Jack says. 
     "Oh, sorry. But do you have any brothers?" 
     "Yes." 
     "Now, if your brother has five apples, and you have eaten three of them, tell me how…?" 
     "He'll certainly give me a good beating" Jack says quickly.
1. How many brothers and sisters does Jack have?
[ ]
A. One brother and one sister.
B. One brother and two sisters.
C. Only one brother.
D. No brothers and no sisters.
2. Why does Mike sometimes hit Jack? Because ______.
[ ]
A. Jack often hits Mike
B. Jack doesn't like eating fruit
C. Jack doesn't do his homework
D. Jack often eats some of Mike's of apples
3. Why can't Jack answer his teacher's question? Because ______.
[ ]
A. he has no sisters
B. he has no brothers
C. he doesn't understand his teacher's question
D. he has no apples
4. If you have five apples, you have eaten three of them, how many apples remain (剩下) ______.
[ ]
A. two
B. three
C. four
D. one
5. When does the story happen (发生)?
[ ]
A. In October.
B. On the ninth day at school.
C. In a new lesson.
D. At school.
判断题