I have a question and I hope someone could help me answer it

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cwtsai987
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I have a question and I hope someone could help me answer it

Post by cwtsai987 » Wed Aug 29, 2007 3:32 pm

I use a book to practice GRE Biology and one of those questions that I am confused of it. I hope somebody could help me. Thanks!

The denaturing of a protein by heat or radiation is caused by the destruction of which structures?
A. Secondary and tertiary
B. Secondary and quarternary
C. Secondary, tertiary and quarternary
D. Tertiary and quarternary
E. Quarternary


The correct answer is A and C is my choice, but I can't understand why the answer is A. I think the quarternary structure is changed by the denaturation of the secondary and tertiary structures.
Last edited by cwtsai987 on Wed Aug 29, 2007 11:39 pm, edited 1 time in total.

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mith
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Post by mith » Wed Aug 29, 2007 5:11 pm

...The correct answer is A, and you picked C...so what is B?

I think the tricky part here is that not every protein has a quaternery structure, so technically you can't denature it for some proteins...
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kotoreru
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Post by kotoreru » Wed Aug 29, 2007 7:05 pm

Hmm what a bad question. I'd go for C.
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MrMistery
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Post by MrMistery » Wed Aug 29, 2007 7:43 pm

Stupid question if the answer is A. I would have also gone with C
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Post by Darby » Thu Aug 30, 2007 1:50 am

Secondary structure is usually a product of bond angles, which aren't strongly affected by the radiations mentioned. As other have said, quaternary isn't always there, but it still seems a better part of a double answer than secondary.

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Post by luay » Thu Aug 30, 2007 2:34 am

not all proteins go to the last phase which is the Quarternary structure so for that simple fact the answer is A. :D

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MrMistery
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Post by MrMistery » Fri Aug 31, 2007 1:05 pm

Yeah but you cannot deny the fact that heat denatures quatenary structure. Of course, it has to be there to get denatured. I guess we just have to agree to disagree
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Post by blcr11 » Fri Aug 31, 2007 2:16 pm

I guess I'm not wild about the possible choices, either. I would argue for A as being correct only because it is possible to disrupt quaternary structure without unfolding or denaturing the subunits. But it is almost certainly true that if you disrupt secondary and tertiary structures, you will per force destroy any quaternary structure as well.

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