Multiple choice questions

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Multiple choice questions

Post by Luna » Sun Feb 24, 2008 9:48 pm

Hey, I have some multiple choice questions that bothesr me. I'll try translating them hoping someone could give me an answear.

1. Hydrophobic interaction in protein is giving important stabilization contributions

a) to proteins secundary- and tertiarystructure.
b) just to the orientation of polar amino acids
c) to the proteins primarystructure
d) after every possible hydrogenbonding are formed
e) only in hydrophobic fases

I am here guessing a or d, but I am very uncertain.

2. The structural membraneproteins are characterized in case of that they

a) don't transport small molecules
b) exist only by beta sheets
c) show prostetic carbohydrate groups on the cytoplasmatic side
d) have a hydrophobic transmembrane domain
e) constitue about 10% of the membrane proteins

Small molecules doesn't use transportproteins so it could be d, but again I'm not certain.

3. In watery solutions proteins conformation is decided by two factors: A maximum of the number of hydrogenbonding and:

a) a minimize av entropy by the formation of a watery shell around the protein
b) a rotation off polar amino acid residues out against the outer shell off the protein
c) a rotation off hydrophobic amino acids sidechains towards the centre of the protein
d) minimize off hydrophobic interactions
e) maximize of ion interaction

Here I actually don't have a clue, but someone told me it could be a?

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Post by MrMistery » Mon Feb 25, 2008 1:48 pm

1. a. C is wrong, as the amino acid sequence is not affected by hydrophobic interactions.
2. I don't know what these "structural" transmembrane proteins are, but if they are transmembrane they definitely need a hidrophobic domain when crossing the membrane, so d is true.
3. more entropy is better, so i don't think it is a. Both b and c seem correct to me, as polar aminos like to sit near water and hydrophobic aminos like to be near each other.
"As a biologist, I firmly believe that when you're dead, you're dead. Except for what you live behind in history. That's the only afterlife" - J. Craig Venter

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Re: Multiple choice questions

Post by Luna » Mon Feb 25, 2008 8:56 pm

Does somebody else have an answear to question 2?

In the formation from S to P will an enzyme change the equilbrium to the product?
And if a enzymreaction have a favourable equilibrium would it have a high reactionrate?

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