锌指蛋白与锌的结合( )。
A．是共价的
B．通过保守的胱氨酸和组氨酸残基间协调进行
C．必须有DNA的存在
D．位于蛋白质的α-螺旋区域
参考答案：B
细菌对氨基糖苷类抗生素形成耐药的主要原因是
A．细菌产生了水解酶B．细菌产生了钝化酶C．细菌膜通透性改变D．细菌代谢途径的改变E．与细菌致死靶位亲合力降低
All of the following are violations of Standard Ⅲ (B), Fair Dealing, EXCEPT a member:（）
A. places a trade for her discretionary accounts before placing a trade for her non-discretionary accounts.
B. places a trade for the firm account before issuing a buy recommendation.
C. telephones clients in distant cities the day after a buy recommendation is mailed to all clients because their mail service is later than the member’s local clients.
