革兰氏阳性菌细胞壁特有的组分是（）
A.脂质
B.脂多糖
C.磷壁酸
D.肽聚糖
E.蛋白质
参考答案：C
解析：细菌的结构与生理，细菌的基本结构革兰氏阳性菌细胞壁：由肽聚糖和穿插于其内的磷壁酸组成。肽聚糖为原核生物细胞所特有，又称黏肽，是构成细菌细胞壁的成分。磷壁酸是革兰氏阳性菌细胞壁的特有成分，依据结合部位的不同可分为壁磷壁酸和膜磷壁酸。【考试科目】《兽医微生物》
Tom and Fred were talking about the year 2050. “What will 36 be like in the year 2050?” asked Tom. “I don’t know,” said Fred. “What do you think?” “Well, no one knows. But it is __37__ to guess,” said Tom. “In the year 2050 everybody will carry a pocket (袖珍) __38___. The computer will give people the __39__ to all their problems. We shall all have telephones in our pockets,__40___ . And we’ll be able to talk to our friends all over the world. Perhaps(也许) we’ll be able to ___41__ them at the same time. Machines will do ___42___of the work, and people will have more__43___. Perhaps they will work only two or three days a week. They will be able to fly to the moon by spaceship and spend their holidays there.” “I’m very _44__to hear that. I hope to fly to the moon. And I hope I’ll be able to live _45___,” said Fred. “Won’t that be interesting? Just like a fish.”
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