看板Biotech
標 題Re: [問題] 一個遺傳的選擇題
發信站清華生命科學 BBS (Sun Jun 17 21:05:53 2007)
轉信站ptt!Group.NCTU!grouppost!Group.NCTU!nthuls
> 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
1F：推 thrush:thank you, but the given answer is D. 06/17 21:26
2F：推 yaliu:為什麼答案是D阿???? 06/18 00:07
3F：推 thrush:Sorry, that also confuse me. 06/18 09:23
4F：推 nightcatman:google可以找到那張考卷,說實在的出得很爛,英文也很爛 06/19 08:02
5F：→ nightcatman:我懷疑是研究生助教幫老師出的... 06/19 08:03
6F：推 b46006:我覺得是E 被切開的地方必須互補不是嗎 06/19 11:37
7F：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 06/19 12:58
8F：推 b46006:樓上真細心 06/19 14:12