2022英语周报高考外研综合第11期答案

Possible version:Tom thought for a moment and was about to agree, but he changed his mind. " I can't, BenYou know Aunt Polly wants the fence to be perfect. It has to be done very carefully.I don'tthink you can do it well enough. "He said to Ben, who looked a little discouraged. "Oh, Tom, I'llbe careful. Please let me have a try I would like to give you my apple if you agree, "requestedBen In the end, Tom gave up the brush with unwillingness on his face, but joy in his heartWhile ben worked at the fence in the hot sun Tom sat under a tree, eating the apple, andlanning how to get more help. many of his other friends walked past him. Each one came topllaugh, but remained to whitewash the fence because they all got interested in it. One by one, theywhitewashed the fence, each giving Tom a reward, big or small. If he hadn't run out ofwhitewash, Tom would have owned everything belonging to his friends. He had a most wonderful andidle Saturday, sitting in the shade and enjoying the rewards that his friends gave him

38.(12分,每空2分)(1)1/32(2)紫花白花=1:1紫花白花=31:1紫花:白花=7:1紫花:白花=7:11/9【解析】(1)如果假设①正确,则亲本的基因型为AA和aa,F1的基因型为Aa,F2中白花植株所占的比率1/(63+1)=164。F1紫花植株产生的雌配子中a的概率为1/2,A配子的概率为1/2,故F1紫花植株产生的可育雄配子中a的概率是(164)/(1/2)=/32(2)验证上述①假设当E1作为母本进行测交时,即Aa×aa,则雌配子中a的概率为1/2,A的概率为1/2,雄配子的基因组成为a,故子代的基因型及比例为Aaa=1:1子代表现型及比例为紫花:白花=1:1当F1作为父本进行测交时,即Aaxa,则雄配子中a配子的概率为1/32,A配子的概率为31/32,雌配子的基因组成为a,故子代的基因型及氵比例为Aa:aa=(31/32):(1/32)=31:1,子代表现型及比例为紫花白花=31:1。验证上述②假设:不管F1作为母本,还是父本,进行测交时,均为AaB-bCc× aabbcc,子代中只有基因型为abec的植株为白花植株,其余均为紫花植株。子代中基因型为abbc植株所占的比例为1/2×1/2×1/2=1/8,故紫花:白花=(1-1/8):(1/8)=7:1。如果实验证明假设②是正确的,F1紫花植株进行自交,即 AaBbCc氵AaBbCc,F2中的紫花植株所占的比例为63/(63+1)=63/64,其中纯种所占的比例为(1/2×1/2×1/2-1/64)/(63/64)=1/9。

以上就是2022英语周报高考外研综合第11期答案，更多英语周报答案请关注本网站。