问题 问答题 简答题

简述火箭免疫电泳的原理。

答案

参考答案:

火箭免疫电泳技术又称作单向电泳扩散免疫沉淀试验,它是由单向扩散发展起来的一项定量技术,实质上是加速度的单向扩散。在含抗体的琼脂板一端打一排抗原孔,加入待测标本后,将抗原置阴极端,用横距2~3mA/cm的电流强度进行电泳。抗原泳向阳极,在抗原抗体比例恰当处发生结合沉淀,随着泳动抗原的减少,沉淀逐渐减少,形成峰状的沉淀区,状似火箭。抗体浓度保持不变,峰的高度与抗原量呈正比,用已知量标准抗原作对照,可以方便地测定未知标本中的抗原含量。 

阅读理解

“A very disruptive(扰乱型的)six-year old child kicked my legs and clawed at my hand.” said one teacher. “I broke up a fight but was kicked,” said another. Many people have heard stories like this. But the situation is more worrying still and it involves(涉及) parents.

Every child, regardless of(不管) the surroundings into which they are born,has the right to achieve their potential. And we recognize that, as a nation,it is a long way to achieve this goal. But rights come with responsibilities and what worries people is that we are in danger of ignoring the latter.

Far too many children are behaving badly at school,even to the point of being violent to teachers. This is terrible enough,but it is hard to be surprised since many children are just mirroring the behavior of their parents. Too many are starting school unable to hold a knife and fork, unused to eating at a table,and unable to use the toilet properly.

We are in danger of becoming a nation of families living separate lives under one roof. The bedroom, once a place to sleep,has become the living space for the young. Spending hours in front of computer screens, on social networking sites or being addicted to computer games, children and young people spend little time with their parents. Parents are unable to monitor just what their children are watching.

Schools cannot right the wrongs of society and teachers cannot become substitute (代替)parents. Both parties need to work together. Parents must be helped and given confidence to take back control. They are responsible for setting limits to their children’s behavior and sticking to those limits when things get tough(困难). They are responsible for setting a good example to their children and for devoting that most precious of resources---time---so that children come to school ready and willing to learn.

小题1:In the opinion of the writer, what problem do people ignore?

A.The school violence.

B.The pressure of students’ learning.

C.The right to achieve students’ potential.

D.the responsibilities of the students.小题2:The writer’s attitude to the behaviors of parents may be ________.

A.dissatisfied

B.unconcerned

C.understanding

D.tolerant(容忍的)小题3:The underlined part in Para 4 may means__________.

A.parents and children live in their separate rooms

B.parents care little about children’s life at home

C.children don’t live with their parents in the same room

D.children spent little time with their parents at home小题4:From the last paragraph, we can infer that______.

A.schools can’t correct the wrongs that society does to teachers

B.teachers have no responsibility for playing the role of parents

C.parents should spend time with children making them ready to learn

D.students are responsible for making themselves known in society

多项选择题