GWD2-Q21

LUCIE_SIMON

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?

1. Telomerase is the only enzyme that is present in cancerous cells but absent from cells that are not actively dividing.

2. In children, the only body tissues from which telomerase is absent are those in which cells are not rapidly dividing.

3. The presence of telomerase in bone marrow is no indication of bone marrow cancer.

4. Cancer of the bone marrow develops more rapidly than cancer growing in any other kind of adult tissue.

5. The level of telomerase production is always higher in cancerous tissue than in noncancerous tissue.

答案是C，我选了B。翻阅过以前的帖子，我还是不知道为什么B不对，为什么C比B好……

请NN们解答~~

LUCIE_SIMON

顶顶~

LUCIE_SIMON

恩，我试着用relevant来做~~

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?

1. Telomerase is the only enzyme that is present in cancerous cells but absent from cells that are not actively dividing.

2. In children, the only body tissues from which telomerase is absent are those in which cells are not rapidly dividing.

3. The presence of telomerase in bone marrow is no indication of bone marrow cancer.

4. Cancer of the bone marrow develops more rapidly than cancer growing in any other kind of adult tissue.

5. The level of telomerase production is always higher in cancerous tissue than in noncancerous tissue.

虽然我没有搞懂为什么B不对，为什么C比B好，但是如果按照逻辑上的relevant思路，逻辑题干都在讲bone marrow， cancer和telomerase这三样东西，按照相关性原则的话只有C是三样东西都有的，而B则完全不相关，所以选C，不选B。

可以这么想吗？？请NN解答

angelautsuzy

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～～

LUCIE_SIMON

以下是引用angelautsuzy在2009-5-19 11:31:00的发言：

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～～

B的意思是说在小孩体内，telemerase只在那些cell dividing不是很快的tissue里是没有的。

你是不是意思理解错了。。。不是tissue is absent。。。。

[此贴子已经被作者于2009-5-20 17:44:37编辑过]

LUCIE_SIMON

顶，大家来解惑啊解惑

msuzengli

想了好久，终于想明白了.

B说，只有那些not rapidly dividing的cells才会缺少Telomerase.其实这是错的.偷换了概念.
因为文中只是说Telomerase只能在rapidly dividing的cells中出现,可是没有说rapidly dividing的cells就一定有Telomerase.

因此，那些rapidly dividing的cells也可能没有Telomerase.

所以B是错的.

这题好难啊~！

jbyupei

楼上说的对， B选项玩了个ONLY

C 选项正确，骨髓中物质的出现不是癌症的标志

LUCIE_SIMON

以下是引用msuzengli在2009-5-21 1:04:00的发言：

想了好久，终于想明白了.

B说，只有那些not rapidly dividing的cells才会缺少Telomerase.其实这是错的.偷换了概念.
因为文中只是说Telomerase只能在rapidly dividing的cells中出现,可是没有说rapidly dividing的cells就一定有Telomerase.

因此，那些rapidly dividing的cells也可能没有Telomerase.

所以B是错的.

这题好难啊~！

恩，我理解你的意思了。

但是这题问的是support，原文的意思说Telomerase只能在rapidly dividing的cells中出现，言下之意不是所有的rapidly dividing的cells都有Telomerase，但是现在B的意思说，所有的rapidly dividing的cells都有Telomerase，那不是加强了么？？？？or 违背了原文的意思？？

qbfnigel

B选是原文Telomerase is an enzyme that is produced only in cells that are actively dividing，的否命题，当然不对啦。其实条件推理的题再GMAT中蛮少的，大家不用太在意。

非NN