enzyme question

[theonlytycrane]

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This is just a typical enzyme question. (B) is the answer, but I was thinking about this- (C) isn't necessarily wrong is it? Enzymes also decrease the entropy of reactants to hold them "in place" to react.

 

[aldol16]

It all depends. An enzyme could serve as a general acid/base and thus not have to "hold the reactants in place." You don't know how exactly the enzyme works, although you could deduce a lot from the mechanism of the reaction it catalyzes.

 

[aalamruad]

View attachment 204000

This is just a typical enzyme question. (B) is the answer, but I was thinking about this- (C) isn't necessarily wrong is it? Enzymes also decrease the entropy of reactants to hold them "in place" to react.

Kind of subtle, but decreasing the entropy of the reactants isn't really what enzymes "serve to do." I'd interpret that phrase as meaning more of "what's the overall relevance of enzymes," rather than "what specific processes do enzymes use to carry out their major functions," although I suppose you're not technically incorrect

 

[Prilozack]

No, entropy is not correct.

 

[aalamruad]

No, entropy is not correct.

Again, please stop posting responses like this. Entropy is actually correct in the case of a lot of enzymes, technically speaking. If you want to help people out in this subforum, then that's great, but you need to start including explanations in your posts.

 

[Prilozack]

Again, please stop posting responses like this. Entropy is actually correct in the case of a lot of enzymes, technically speaking. If you want to help people out in this subforum, then that's great, but you need to start including explanations in your posts.

No, entropy is referring to thermodynamic processes, so it is not kinetic property. That's the key to this question. Sorry for the unclear response.

 

[bararaboi]

The change in entropy of the reaction will be the same; Entropy refers to some intrinsic value specific to that compound (the reactants or products, for example). Regardless of how you change the way you get there, the change in entropy will be the same.

 

[aldol16]

No, entropy is referring to thermodynamic processes, so it is not kinetic property. That's the key to this question. Sorry for the unclear response.

Your distinction is not valid. An entropic argument for the reactants would have a so-called ground state effect of raising the activation barrier. Draw a reaction coordinate diagram and convince yourself of this. If you raise the energy of the reactants, they will face a lower kinetic barrier - this is a ground state effect again.

What you are referring to is an overall change in entropy of the reaction, which in fact does not have a kinetic effect. Here, they are talking about the absolute entropy of the reactants and decreasing the entropy of the reactants would have the effect of raising the free energy of the reactants, thereby lowering the activation barrier. This is actually a crucial component of the so-called kinetic isotope effect.

 

[aldol16]

The change in entropy of the reaction will be the same; Entropy refers to some intrinsic value specific to that compound (the reactants or products, for example). Regardless of how you change the way you get there, the change in entropy will be the same.

See above about the distinction between absolute entropy of reactants and the change in entropy of the reaction.