题目内容

下列碱基只存在于RNA,而不存在于DNA的是

A. 尿嘧啶
B. 腺嘌呤
C. 胞嘧啶
D. 鸟嘌呤
E. 胸腺嘧啶

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人体最早的造血器官是

A. 胸腺
B. .肝
C. .脾
D. 骨髓
E. 卵黄囊

"Before the operation, I would look at someone and all I could see for their face was jelly," says Jonathan Wyatt "Now, I can see people"s faces." The 65-year-old is one of six people in the world to receive gene therapy for a【C1】______type of inherited eye disease【C2】______choroideremia(an eye disease). The first published【C3】______of the trial, released today, suggest that【C4】______people"s genes can stop the disease from causing blindness—and【C5】______sight in those whose vision has become【C6】______. Choroideremia is caused by【C7】______in the CHM gene. In those who have the disease, a【C8】______of REP-1 means that cells in the eyes stop working and slowly begin to【C9】______causing blindness. Enter gene therapy, which uses a virus to insert a【C10】______copy of a gene into cells with a gene defect and could【C11】______be used to treat many genetic conditions. Robert MacLaren of the University of Oxford and his colleagues decided to see if it could【C12】______choroideremia. Starting two years ago with Wyatt, they【C13】______a virus carrying a corrective copy of the CHM gene into the eyes of people with choroideremia. Today the team【C14】______that of the six people who received the treatment six months【C15】______or longer, all have described【C16】______in their vision. Still, the long-lasting effects of the treatment remain【C17】______Wyatt had the treatment first, so can【C18】______that the benefits seem to last two years,【C19】______he"s just one case. The treatment also can"t replace cells that have been【C20】______destroyed. 【C18】

A. regard
B. advise
C. predict
D. reveal

急性白血病的骨髓象诊断标准是

A. 白血病细胞比例>20%
B. 白血病细胞比例>30%
C. 白血病细胞比例>40%
D. 白血病细胞比例>50%
E. 白血病细胞比例>90%

正常骨髓象粒/红细胞比例为

A. 1:5
B. 1:(3~4)
C. 1:1
D. (3~4):1
E. 5:1

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