Re: Iddo's test 4, questions 9 and 10
Gayle K. Schulte (schulteg@pfizer.com)
Tue, 13 Feb 1996 04:20:53 -0500 (EST)
Reply to Luis's questions regarding Iddo's Self-Assessment
Quiz #4. Don't read any further if you don't want to.
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>
>
> If I understood the questions, they concern the chirality of the
> beta-carbon. I identify the aminoacids as:
>
> a: L-Thr, configuration of the beta carbon = R
> b: L-Thr, configuration of the beta carbon = S (L-alo-Thr)
>
> c: L-Ile, configuration of the beta carbon = R
> d: L-Ile, configuration of the beta carbon = S
>
The identification of your amino acid's beta carbon as R or S
is correct. The configuration of the naturally occurring isoleucine
is not "c" but "d", so in Iddo's test, the correct answer is "2",
that is "a and d".
An easy way to remember this is to think th"R"eonine and i"S"oleucine!
>
> As to question 10, I think these are the only two aminoacids with
> asymmetric beta carbon. However, 2 is not among the choice of answers.
>
I think the problem you are having with question 10 is how you are
reading it. There are no other amino acids that could have been
included in question 9, so the answer is "0" which is answer #1.
Gayle