英语周报2020--2021高考版第十一期答案

25.(8分,除标注外,每空1分)(1)AaBb丙(2)第一极体de(3)龙胆紫溶液或醋酸洋红溶液(4)减数第一次分裂后期同源染色体1号与2号没有分开(2分)(5)基因突变或同源染色体中非姐妹染色单体间交叉互换【解析】(1)甲细胞处于有丝分裂后期,分裂产生的子细胞的基因型与母细胞基因型相同,即AaBb。乙细胞处于减数第一次分裂前期。丙细胞处于减数第二次分裂后期,不具有同源染色体(2)丙图细胞细胞质均等分裂,是第一极体,染色体数目变化对应丁图的de段3)用光学显微镜观察到图中细胞所示的染色体,篙用龙胆紫溶液或醋酸洋红溶液染色(4)若乙图细胞分裂完成后形成了基因型为AaB的子细胞,其原因最可能是1号与2号染色体在减数第一次分裂后期没有正常分离(5)该动物进行减数分裂的细胞中姐妹染色单体上出现等位基因,原因是发生了基因突变或同源染色体中非姐妹染色单体间交叉互换

As a matter of fact, every day in every way that little elf was a nag(喋喋不休的人! Patrickwas working harder than ever and it was a drag! He was staying up nights, had never felt so weary,and was going to school with his eyes puffed and bleary. Finally, the last day of school arrived andthe elf was free to go. As for homework, there was no more, so he quietly and slyly slipped out theback doorPatrick got his As. His classmates were amazed His teachers smiled and were full of praiseAnd his parents? They wondered what had happened to Patrick. He was now the model kid. Hecleaned his room, did his chores, cheerful and never rude, like he had developed a whole newattitude. You see, in the end, Patrick still thought he'd made that tiny man do all his homeworkBut I'll share a secret just between you and me. It wasnt the elf. Patrick had done it himself

以上就是英语周报2020--2021高考版第十一期答案，更多英语周报答案请关注本网站。