问题 单项选择题 A1型题

具有免疫记忆功能的细胞是()

A.B细胞

B.巨噬细胞

C.肥大细胞

D.NK细胞

E.中性粒细胞

答案

参考答案:A

解析:反应阶段又称增殖与分化阶段,此阶段是抗原特异性淋巴细胞识别抗原后活化,进行增殖与分化,以及产生效应性淋巴细胞和效应分子的过程。T淋巴细胞增殖分化为淋巴母细胞,最终成为效应性淋巴细胞,并产生多种细胞因子:B细胞增殖分化为浆细胞,合成并分泌抗体。一部分T、B淋巴细胞在分化的过程中变为记忆性细胞(Tm和Bm)。这个阶段有多种细胞间的协作和多种细胞因子的参加。B细胞在活化信号的刺激下,由G0期进入G1期,IL-4可诱导静止的B细胞体积增大,并刺激其DNA和蛋白质的合成。活化的B细胞表面可依次表达IL-2、IL-4、IL-5、IL-6等细胞因子受体,分别与活化的T细胞所释放的IL-2、IL-4、IL-5、IL-6结合,然后进入S期,并开始增殖分化成成熟的浆细胞,合成并分泌抗体球蛋白,一部分B细胞在分化过程中变为记忆性B细胞(Bm)。在B细胞的活化过程中,与B细胞抗原受体(BCR)复合体中的Ig-α/Ig-β异二聚体在抗原信息传递中具有重要的作用,认为是一种信息传递分子。作为抗原递呈细胞的B细胞在递呈抗原的同时自身也活化

填空题
单项选择题

For me, scientific knowledge is divided into mathematical sciences, natural sciences or sciences dealing with the natural world (physical and biological sciences), and sciences dealing with mankind (psychology, sociology, all the sciences of cultural achievements. every kind of historical knowledge).

Apart from these sciences is philosophy, about which we will talk later. In the first place, all this is pure or theoretical knowledge, sought only for the purpose of understanding, in order to fulfill the need to understand that is intrinsic and con-substantial to man. What distinguishes man from animals is that he knows and needs to know. If man did not know that the world existed, and that the world was of a certain kind, that he was in the world and that he himself was of a certain kind, he wouldn’t be man. The technical aspects or applications of knowledge are equally necessary for man and are of the greatest importance, because they also contribute to defining him as man and permit him to pursue a life increasingly more truly human.

But even while enjoying the results of technical progress, man must defend the primacy and autonomy of pure knowledge. Knowledge sought directly for its practical applications will have immediate and foreseeable success, but not the kind of important result whose revolutionary scope is for the most part unforeseen, except by the imagination of the Utopians. Let me recall a well-known example. If the Greek mathematicians had not applied themselves to the investigation of conic section zealously and without the least suspicion that it might someday be useful, it would not have been possible centuries later to navigate far from shore. The first men to study the nature of electricity could not imagine that their experiments, carried on because of mere intellectual curiosity, would eventually lead to modern electrical technology, without which we can scarcely conceive of contemporary life.

Pure knowledge is valuable for its own sake, because the human spirit cannot resign itself to ignorance. Butt in addition, it is the foundation for practical results that would not have been reached if this knowledge had not been sought disinterestedly.

Why is electrical technology mentioned in the third paragraph()

A.To confirm its importance in the modern world

B.To show the powerful influence of its inventions

C.To verify the usefulness of theoretical knowledge

D. To give an example of success in practical science