问题
单项选择题
下列哪个药不属于影响核酸合成药
A．5-氟尿嘧啶
B．6-巯基嘌呤
C．甲氨蝶呤
D．塞替派
E．阿糖胞苷
答案
参考答案：D
解析： 塞替派是乙酰亚胺类烷化剂的代表，所含烷基能与细胞的DNA、RNA或蛋白质中亲核基团起烷化作用，常可形成交叉联结或引起脱嘌呤，使DNA链断裂，在下一次复制时，又可使碱基配对错码，造成DNA结构和功能的损害。
搜题请搜索小程序“爱下问搜题”
下列哪个药不属于影响核酸合成药
A．5-氟尿嘧啶
B．6-巯基嘌呤
C．甲氨蝶呤
D．塞替派
E．阿糖胞苷
参考答案：D
解析： 塞替派是乙酰亚胺类烷化剂的代表，所含烷基能与细胞的DNA、RNA或蛋白质中亲核基团起烷化作用，常可形成交叉联结或引起脱嘌呤，使DNA链断裂，在下一次复制时，又可使碱基配对错码，造成DNA结构和功能的损害。
完形填空 （10%） A young man works hard on his lessons. He is very busy studying. He doesn’t have __1__ to rest. After sometime, he falls ill. Every night, when he goes to bed, he __2__ his eyes and tries to sleep. But he can’t. He thinks, “I must go to __3__ the doctor.” He tells the doctor, “I can’t go to sleep at night.” “Try counting(数) __4__ . When you reach 1,000, you’ll be asleep,” says the doctor. The next day the man goes back to the doctor’s office. “Well,” says the doctor, “__5__ are you today?” “Well,” the man says, “I tried counting one, two, three … up to 1,000. __6__ when I reached 569, I began __7__ feel sleepy(犯困的). I had to __8__ and __9__ some tea. Then I went on counting up to 1,000 again. But I __10__ couldn’t fall asleep.”
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