题干

在体外培养时,淋巴因子IL-2(—种分泌蛋白)依赖型细胞CTLL-2在不含IL-2的培养基中很快死亡,而在含IL-2的培养基中可在体外长期培养,且在一定的IL-2浓度范围内,细胞增殖与IL-2的含量呈正比。下列说法错误的是(    )

A:CTLL-2细胞表面分布着与IL-2特异性结合的受体

B:选用生理状态相同的CTIL-2细胞有利于提高实验的准确性

C:通过测定CTLL-2细胞增殖情况可判断培养基IL-2的含量

D:IL-2通过抑制原癌基因和抑癌基因的表达而影响细胞增殖

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答案(点此获取答案解析)

D

同类题4

阅读下面短文,掌握其大意,从每题所给的A、B、C、D四个选项中,选出最佳选项。

    If life were a book and you were the author, how would you like the story to go? That is the question that 1 my life forever.

    One day I went home from the training of snowboarding with what I thought was the flu, and less than 24 hours later, I was in a 2 on life support with less than two percent 3 of living. It wasn't until days later that the doctors diagnosed me with a 4 blood infection.

    Over the 5 of 2.5 months, I lost the hearing in my left ear and both my legs below the knee. When my parents 6 me out of the hospital, I 7 that I had been put together like a patchwork(拼缝物) doll and I had to live with 8 legs. I was absolutely physically and emotionally broken, 9 streaming down.

    But I knew in order to move forward, I had to let go of the Old Amy and 10 the New Amy. It was at this moment that I asked myself that significant 11. And that is when it 12 me that I didn't have to be five-foot-five anymore,13 I could be as tall as I wanted. And 14 of all, I can make my feet the size of all the shoes. So there were 15 here.

    Four months later, I was back upon a 16. And this February, I won two Board World Cup gold medals, 17 me the highest ranked snowboarder in the world.

    So, instead of looking at our 18 and our limitations as something 19 or bad, we can begin looking at them as a wonderful 20 that can be used to help us go further than we ever know we could go.