问题 问答题 简答题

分子生物学测定方法的方法学评价。

答案

参考答案:

主要用于测定细胞因子的基因水平和转录水平。可用于细胞内发生的细胞因子的基因突变、缺失、重排及染色体易位等的检测;可得到特定的病理情况下何种细胞中特异DNA序列发生了何种改变;揭示细胞中细胞因子基因的特定改变及其表达究竟发生在细胞增殖周期的哪个阶段及其与细胞形态学之间的关系;可用于探讨细胞因子基因的改变与特定疾病发生发展之间的关系。

单项选择题
阅读理解
A new study has found no evidence that sunscreen, commonly used to reduce the risk of skin caner, actually increases the risk.
Researchers from the University of Yale based their findings on a review of 18 earlier studies that looked at the association between sunscreen use and melanomas (黑素瘤). They said that they found flaws in studies that had reported associations between sunscreen use and higher risk of melanoma.
Most health experts believe that by protecting the skin from the harmful effects of the sun, sunscreen helps prevent skin cancer, which is increasing in incidence (发生率) faster than any other cancer in the United States.
But questions have been raised about sunscreen and whether it may have the opposite effect, perhaps by allowing people to remain exposed to the sun longer without burning.
The researchers said that among the problems with some earlier studies is that they often failed to take into account that those people most at risk for skin cancer—people with fair skin and freckles (雀斑), for example—are more likely to use sunscreen. As a result, it may appear that sunscreen users get cancer more often.
The studies, which generally relied on volunteers to recall their sunscreen use, were also unable to prove how well the products had been applied, said the new study.
小题1:The underlined word “flaws” in the 2nd paragraph most probably means           .
      
A.evidencesB.factsC.faultsD.failures
小题2:People with fair skin and freckles           .
      
A.seldom use sunscreenB.are more in danger of skin cancer
C.can be free from the harm of the sunD.often expose themselves to the sun
小题3:We can learn from the passage that          .
      
A.sunscreen users get skin cancer more often
B.the volunteers have proved the effect of sunscreen
C.the new study was based on the experiences of volunteers
D.the number of skin cancer patients is increasing in America
小题4:Which of the following can be the best title for this passage?
      
A.Sunscreen to Prevent Skin Cancer
B.Sunscreen to Increase Skin Cancer
C.Skin Cancer Caused by Sunscreen
D.Skin Cancer Caused by Freckles