【单选题】在乙型脑炎病毒的流行环节中,下列哪项是错误的?
【简答题】DNA 复制时为什么前导链是连续复制,而后随链是以不连续的方式复制?并请以大肠杆菌为例简述后随链复制的各个步骤。
【单选题】—Do you have trouble finding the house? —______.
【简答题】The car was completely _____ and the driver seriously injured. A. broken off B. taken off C. written off D. picked up
【简答题】—Do you have trouble finding the house? —___________. A.No,completely none B.Yes,completely none C.No,hardly one D.Yes,I’ve got one
【简答题】DNA复制时3'-5'链模板链的合成是5'-3'方向,其合成是连续的,同复制叉向前推进的方向一致,这条链称为前导链(leading strand);而对于5'-3'方向模板链的互补链的合成是3'-5'方向,其合成是不连续的,这条链称为滞后链/后随链(lagging strand),长度大约1000-2000b,又称( )。
【单选题】下列关于DNA复制特点的描述,哪项是正确的
【简答题】A completely new situation will _____ when the examination system comes into existence. (A) arise (C) raise (B) rise (D) arouse