题目

下列选项符合图示含义的是（ ） A．随pH从5升高到7，酶的活性逐渐降低 B．随pH从5升高到7，酶的最适温度不变 C．温度从O→A变化过程中，酶的活性逐渐降低 D．该酶的最适pH为7 答案：解：A、随pH值从5升高到7，酶的活性先升高后降低，A错误； B、随pH值从5升高到7，酶的最适温度始终为A，B正确； C、温度从O→A变化过程中，酶的活性逐渐升高，C错误； D、pH值为6时反应物剩余量最少，该酶的最适pH值为6，D错误． 故选：B．词汇运用。1. His left knee was hurt in a t_______ accident.2. I am a hundred p_______ in agreement with you.3. I have an a_______ with my doctor this afternoon.3. The number of population _______ (increasing) quickly. 5. The population of this city _______ (be) not large.6. Those poor children need somewhere _______ (live). 7. You should protect the children from _______ (catch) cold.  8. How long does it take you _______ (walk) 50 meters? 9. That easy chair takes up too much _______ (room).