第12题: [单项选择]Which of the following is a feature of a unit of work?() A. It applies to a single data server. B. It is a recoverable sequence of operations. C. Its value can be queried from the system catalog tables. D. It begins when the application connects to the data server. 参考答案:B
第27题: [单项选择]下面说法,错误的是 A. 补体组分C1是由C1Q、C1r、C1s三个糖蛋白亚单位组成 B. 补体成分C4是一种β球蛋白,由三条多肽链组成 C. 补体组分C2是一种γ球蛋白 D. 补体组分C3是一种β球蛋白,由两条多肽链组成 E. 补体组分C5是一种β球蛋白,由两条多肽链组成 参考答案:C 答案解析:[解析] 补体组分C2为丝氨酸蛋白酶原,为单链的β球蛋白,其血浆浓度很低,是补体活化级联酶促反应的限速步骤。