问题 实验题

牛的毛色有黑色和棕色,如果两头黑牛交配产生了一头棕色小牛,请回答:(每空2分,8分)

(1)黑色和棕色哪种是显性性状          

(2)如果用B与b表示牛的毛色的显性基因和隐性基因,写出上述两头黑牛的基因组成        

(3)这头棕色小牛的基因组成         

(4)这两头如果生出黑色小牛,其基因组成可能是         

答案

两头黑牛交配产生了一头棕色小牛,则棕色为隐形性状,黑色为显性性状;双杂合Bb×Bb(黑色)可以产生bb(棕色),与题意相符;如果生出黑色小牛,其基因组成可能为BB或Bb两种。

写作题

读写任务。

阅读下面的短文, 然后按照要求写一篇150词左右的英语短文。

     CHICAGO (Reuters)-Smoking not only can wrinkle(起皱纹) the face and turn it yellow-it can do

the same to the whole body, researchers reported on Monday.

     The study, published in the Archives of Dermatology, shows that smoking affects the skin all over

the body-even skin protected from the sun.

    “We examined nonfacial skin that was protected from the sun, and found that the total number of

packs of cigarettes smoked per day and the total years a person has smoked were linked with the

amount of skin damage a person experienced, ” Dr Yolanda Helfrich of the University of Michigan, who

led the study, said in a statement.

   “In participants older than 65 years, smokers had significantly more fine wrinkling than nonsmokers.

Similar findings were seen in participants aged 45 to 65 years, ” Helfrich's team added in their report.

     The researchers tested 82 people, smokers and nonsmokers, taking pictures of the inner right arms.

They ranged in age from 22 to 91 and half were smokers.

[写作内容]

1.以约30个词概括短文内容。

2. 以约120个词就在校青少年吸烟的现象进行分析, 至少包括以下的内容要点:

(1)描述青少年尤其是高中生吸烟的现状;

(2)分析青少年吸烟的原因。

[写作要求]

可以使用实例来支持你的论点, 也可以参照阅读材料的内容, 但不要直接引用阅读材料中的句子。

[评分标准]

概括准确,  语言规范,  内容合适,  篇章连贯。

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