选修内容比必修深 ,教学有难度 ,要显效 ,宜兼顾两者。如第 5 3页 ,乳糖代谢基因表达调控图解 ,若让学生记住结构基因的左边先是操纵基因 ,接着是启动子 ,最末是调节基因 ,这未免枯燥 ,也不宜用“书读百遍其义自见”来勉励学生。应回顾必修本上的“基因是有遗传效应的 DNA片段 Elective content than compulsory, teaching difficult, to be effective, should take into account both. If page 5 3, lactose metabolism gene expression control diagram, if the students remember the left side of the structural gene manipulation of the gene, followed by the promoter, the last is the regulation of genes, it is too boring, it is not appropriate to use “the book read a hundred times its Righteousness from see ”to encourage students. It is recalled that the “gene” is a genetically-engineered segment of DNA