本贴相关题目 TN-24-CR-31 (KBWE)

00:00:00

Telomerase is an enzyme that is produced only in cells that are actively dividing. For this reason it is generally absent from body tissues in adults. Bone marrow is an exception to this rule, however, since even in adults, bone marrow cells continually divide to replace old blood cells. Cancers are another exception, because their cells are rapidly dividing.

The information provided most strongly supports which of the following?

ATelomerase is the only enzyme that is present in cancerous cells but absent from cells that are not actively dividing.
BIn children, the only body tissues from which telomerase is absent are those in which cells are not rapidly dividing.
CThe presence of telomerase in bone marrow is no indication of bone marrow cancer.
DCancer of the bone marrow develops more rapidly than cancer growing in any other kind of adult tissue.
EThe level of telomerase production is always higher in cancerous tissue than in noncancerous tissue.

正确答案: C

GWD2-Q21

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angelautsuzy

楼主

发表于 2009-5-19 11:31:00 | 显示全部楼层

我是这么想的：题目说 telomerase 只能produce在 actively diving 的cells，所以成人体内没有这个。但是 bone marrow是个特例，因为bone marrow 在成人体内也devide。然后cancer也是一个特例，因为cancer,也就是肿瘤的细胞也在dividing。

所以分解B的题干就是 in children, the only body tissues is absent, absent 的原因是cell 不dividing。题目里面没有将说不dividing的cell就不能存在在孩子体内。只是说有些生物体必须存在在dividing的cell 里面。所以我觉得B貌似完全没有依据。尤其 the only 在这里显得很武断的感觉，孩子体内maybe缺少很多成人的一些cell吧。

C。 telomerase的存在（在bone marrow）不能代表就是bone marrow cancer。因为 bone marrow本身cell在快速dividing，提供了telomerase生长环境。

生物不好，但是我猜想应该是telemerase存在在cancel里面，就会导致癌变吧，或者cancer在bone marrow里面长就会变成bone marrow cancer？乱说的这里，有明白的同学给指点下吧～～