Re: [問題] 一個遺傳的選擇題

> A restriction enzyme cuts DNA and leaves the following end: GGCTA
>                                                             C
> Which of the following could be the sequence of the corresponding end of the
> other fragment generated by the enzyme?
> A) CCGAT
>    G
> B) GGCTA
>    C
> C) C
>    GGCTA
> D) T
>    CGATA
> E> None of the above


I think this is a very tricky question (and a controversial one).
Normally a restriction enzyme cutting site needs to be symmetrical.
Therefore the complete sequence of the cutting site should be


 5'  GGCTAGCC...3'
 3'  CCGATCGG...5'

After digestion, it becomes

  5' GGCTAGC      C...3'
  3' C      CGATCGG...5'

Therefore, answer B seems to be a reasonable choice.
At least this is probably the professor who designed the quiz wants.

However, I really think this kind of quiz is misleading and will not
be useful in seleting good students.




--
※ Origin: 生命科學 BBS <bbs.life.nthu.edu.tw> 
◆ From: 61-59-139-151.adsl.static.seed.net.tw
推 thrush:thank you, but the given answer is D.
推 yaliu:為什麼答案是D阿????
推 thrush:Sorry, that also confuse me.
推 nightcatman:google可以找到那張考卷,說實在的出得很爛,英文也很爛
→ nightcatman:我懷疑是研究生助教幫老師出的...
推 b46006:我覺得是E 被切開的地方必須互補不是嗎
推 blence:D,是因為排版的問題T沒有正確配對,把上面T拉到正確位就對了
推 b46006:樓上真細心