受体是()
A.配体的一种
B.酶
C.第二信使
D.蛋白质
E.神经递质
参考答案:D
解析:受体是存在于细胞膜或细胞内,能识别、结合特异性配体,并介导细胞信号转导的功能蛋白质
-He __________ his mother do the housework at the age of eight.
-We should help our parents with the housework. I did it when I __________ six.
A. helped, was
B. helps, was
C. helped, am
D helped, am
安定注射液(含40%丙二醇和10%乙醇)与5%葡萄糖注射液配伍析出沉淀,其原因是()
A.pH值改变
B.离子作用
C.溶剂组成改变
D.盐析作用
E.直接反应