protein questions

[joonkimdds]

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1. when a protein is denatured, which of the following would probably NOT affected?

answer choices:
a) primary
b) secondary
c) hydrogen bonds
d) tertiary
e) all of them are affected


2. which of the following is NOT associated with allosteric regulation of an enzyme's activity?
a) the enzyme usually has two or more polypeptide chains
b) inhibitor and activator molecules may compete with one another
c) regulatory molecules bind to a site remote from the active site
d) the binding of an allosteric inhibitor molecule stabilizes the inactivve form of the enzyme
e) a molecule mimics the substrate and competes for the active site

 

[wigglytooth]

1. when a protein is denatured, which of the following would probably NOT affected?

answer choices:
a) primary
b) secondary
c) hydrogen bonds
d) tertiary
e) all of them are affected


2. which of the following is NOT associated with allosteric regulation of an enzyme's activity?
a) the enzyme usually has two or more polypeptide chains
b) inhibitor and activator molecules may compete with one another
c) regulatory molecules bind to a site remote from the active site
d) the binding of an allosteric inhibitor molecule stabilizes the inactivve form of the enzyme
e) a molecule mimics the substrate and competes for the active site

1. a -- the primary structure is the basic sequence of nucleotides. denaturation will probably mess up weak hydrogen bonds and side-chain bonding before messing up the stronger links that form on the DNA backbone.

2. e -- this describes competitive inhibition, not allostery

 

[joonkimdds]

1. a -- the primary structure is the basic sequence of nucleotides. denaturation will probably mess up weak hydrogen bonds and side-chain bonding before messing up the stronger links that form on the DNA backbone.

2. e -- this describes competitive inhibition, not allostery

OMG!! ur avatar is so cute! I love it!
I go to research about mice 3 days a week and ur avatar is cuter than the ones i play around with.
I do experiment with white mice with red eyes, but i prefer white mice with black eyes just like urs.

 

[cdmOMR]

1. when a protein is denatured, which of the following would probably NOT affected?

answer choices:
a) primary
b) secondary
c) hydrogen bonds
d) tertiary
e) all of them are affected


2. which of the following is NOT associated with allosteric regulation of an enzyme's activity?
a) the enzyme usually has two or more polypeptide chains
b) inhibitor and activator molecules may compete with one another
c) regulatory molecules bind to a site remote from the active site
d) the binding of an allosteric inhibitor molecule stabilizes the inactivve form of the enzyme
e) a molecule mimics the substrate and competes for the active site

For 1 I would say primary. Denaturing I think is generally considered to be unfolding. If the primary is affected, that would mean the protein is completely disassembled which I believe would take some sort of acid hydrolase.

For 2 I would say A also. I looked up allosterism in my Med. dictionary and it said basically a binding site on the enzyme that is occupied by something other than a substrate that alters the enzymes activity. B,C,D, and E all allude to binding to the enzyme to change activity. A, while true, doesnt really seem to have anything to do with allosteric regulation.

These are just guesses, trying to test my own knowledge a bit.

EDIT: I can see the answer being E, but can someone tell me why A has anything to do with allosterism?

 

[joonkimdds]

For 1 I would say primary. Denaturing I think is generally considered to be unfolding. If the primary is affected, that would mean the protein is completely disassembled which I believe would take some sort of acid hydrolase.

For 2 I would say A also. I looked up allosterism in my Med. dictionary and it said basically a binding site on the enzyme that is occupied by something other than a substrate that alters the enzymes activity. B,C,D, and E all allude to binding to the enzyme to change activity. A, while true, doesnt really seem to have anything to do with allosteric regulation.

These are just guesses, trying to test my own knowledge a bit.

EDIT: I can see the answer being E, but can someone tell me why A has anything to do with allosterism?

My guess is that allosteric happens when there are about 4 subunits of proteins are there. so if one of the active site is filled then all 4 active sites are stabilized or something like that.

 

[wigglytooth]

My guess is that allosteric happens when there are about 4 subunits of proteins are there. so if one of the active site is filled then all 4 active sites are stabilized or something like that.

You don't necessarily need 4 subunits, although a classic example of allostery in a 4 subunit protein is hemoglobin. Basically enzymes are typically multisubunit (at least two) and the binding of an effector at an allosteric site changes the shape of that subunit, and helps the other subunit become more stable (or unstable, if the effector is an inhibitor). If the other subunit is also bound by an effector, the whole system will be enhanced (or destabilized, if the effector is an inhibitor). This "helping" between subunits due to an change induced by the binding of an allosteric site is how A fits as an answer. I hope that makes sense, I'm kind of not awake yet.

ps Thanks for the avatar compliment, Joon. www.cuteoverload.com for all your cute needs!