关于肾小球滤过膜通透性的说法，错误的是 （）
A.取决于通过物质的分子量及所带电荷
B.物质分子量越小越容易通过
C.带正电荷的物质较容易通过
D.球蛋白较容易被滤过
E.葡萄糖可自由滤过
参考答案：D
解析：当机体的循环血液流经肾小球时，由于肾小球滤过膜的屏障作用，血液中的细胞成分及大部分血浆蛋白无法通过，而其余成分几乎全部被滤入肾小囊腔内，形成肾小球滤过液，称为原尿。 滤过膜的通透性主要取决于被滤过物质相对分子质量大小及其所带的电荷物质。正常情况下，肾小球滤过膜只允许相对分子质量小于1.5万的小分子物质自由滤过，1.5万～7万的物质可部分通过，而相对分子质量大于7万的物质（如球蛋白、纤维蛋白原等）几乎不能通过；带正电荷的物质较易被滤过，而带负电荷的物质则较难通过滤过膜。因此本题的答案是D。
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| A Man Named Lawrence This is an act of kindness that happened to me one Sunday morning. It was at two o'clock in the morning. We just came out of a club and were trying to find our 1 back to our city. As we were trying to 2 the bus stop, a man came to us and said he would show us 3 it was. Although we were a little 4 , we had no choice but follow him. He told us he was a homeless man and that his name was Lawrence. When we passed some city workers 5 the streets, they sprayed (喷溅) the homeless man. Lawrence told us that they always sprayed the 6 if they were "in the way". I didn't know why they would do that. They were human beings, 7 , not cattle or objects. This man had just gotten 8 in the middle of a cold night, but 9 shouting at the workers, he asked them, "How would you 10 if your father or grandfather were treated like this?" He then told us, "It's 11 use shouting at them, because they just get angry. You're better off saying something from the 12 ." It is 13 ! The world could be so different if only we put our anger 14 , lowered our voices and tried to speak from our hearts. He took us safely to the stop and on the way talked about everything. We 15 him and told him that we 16 have never found the place on our own. He said, "I have a son of your age, and I hope that if he were 17 , someone would help him." Not only did Lawrence clear out all the fear and distrust in our hearts, he helped us find our way, in more than one ways. 18 , this man taught us kindness. There was 19 we could really do to repay him. The only thing I hope to do is to 20 other people out. | ||||
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