2022 英语周报 九年级 GZ 20答案

25.(除标注外,每空2分,共13分)(1)耐高温引物(2)启动子、终止子抗原一抗体杂交(3)共用一套密码子(4)⑥(1分)抗原蛋白质在宿主细胞内能持续表达【解析】本题考查基因工程基本过程、基因表达载体的组成、目的基因的检测与鉴定。(1)与体内DNA复制相比,过程①PCR技术所需酶应具有耐高温的特点,欲选择性扩增出S基因的DNA,前提是利用S基因设计出特异性的引物。(2)构建基因表达载体时应将目的基因插入载体的启动子、终止子之间;要检测⑥是否表达出S蛋白,可用抗原一抗体杂交。(3)病毒的RNA能在人体细胞中表达出病毒的蛋白质,这说明了生物界共用一套密码子。(4)与注入灭活的或减毒的病毒抗原相比,核酸疫苗的突出特点是⑥抗原蛋白的合成是在宿主细胞内进行的。由此推测核酸疫苗一次接种即可获得长期免疫力,无需反复多次加强免疫的原因是抗原蛋白质在宿主细胞内能持续表达。【刷有所得】目的基因的检测与鉴定:检测受体细胞是否含有目的基因用DNA分子杂交技术;检测目的基因是否转录用分子杂交技术检测目的基因是否翻译用抗原一抗体杂交技术。

第二节书面表达【写作思路】根据试题要求,考生需要写一篇记叙文,记述身边一位值得尊敬和爱戴的人。首先考生需要介绍自己最尊敬和爱戴的人是谁,简单地介绍一下他(她)。然后,陈述为什么他(她)值得尊敬和爱戴。最后,可以对前文进行一个总结,使文章结构严谨。本文的写作重点在"尊敬和爱戴的原因",考生可围绕这个要点适当拓展,从性格特点、处事风格等方面展开写作。【范文赏读】The most beloved and respected person around me is my teacher, Ms LiThough she has been teaching English for twenty years, she is still passionateabout teaching. She is kind and considerate towards us just like our dear motherWe all respect her because she always tries new ways to make her classes livelyand interesting. Hardworking and knowledgeable, she is one of the best teachersin our school. When we have a problem, we will turn to her for help. She alwaystalks to us patiently and helps us to find a solution. In our eyes, she is not onlyour teacher, but also our best friend. Those are why she deserves our respect【亮点词句】亮点词汇: beloved, respected, be passionate about, be consideratetowards, turn to sb. for help, in one's eyes亮点句式:Why引导的表语从句( why she deserves our respect)

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