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Previous Topic | Next Topic  NB F1- Which substance will accumulate? V-W-X-Y 




 
Kaplan Qbank USMLE



Author11 Posts
  #1

Amitdoc2b, this was the initial question...



...........ΔG0'
V ↔ W – 4.0
W ↔ X +0.4
X ↔ Y – 3.4
Y ↔ Z + 5.7

From the values of ΔG0' given in the table, which compound in the overall metabolic pathway V ↔ W ↔ X ↔ Y ↔ Z will accumulate in the largest amount at equilibrium?

A) V
B) W
C) X
D) Y
E) Z

On your 2nd question, you assigned the value of
Y ↔ Z + 7.7
Now, which substance will accumulate?


  #2

I sent the qs to Dr Barbara Hansen and she kindly sent me this explanation, so don't panic cause here is the right answer with no doubts. So, just read it, understand it and take a break tomorrow man, wish you the best of luck for the exam




  #3

I calculated the values for each of the substances just to make sure I got the concept, and I got this...



So, Yes, Y will accumulate the most, in number and also b/c it is an spontaneous reaction.

Again Good luck in your exam amitodc2b


Edited by Musuq on 08/29/06 - 11:45 PM

  #4

thanku for taking so much trouble to explain a difficult q.

  #5

thanks buddy - totally agree with docsrinu.

  #6

hey tht's really good, tht u asked dr.hansen, kool man i was right earlier but for the wrong reasons, but now the picture is very clear! thanks a lot! good work

Edited by ssrpk on 08/30/06 - 11:34 AM

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  #7

thanx a lot musuq excellent concept

  #8

wink

  #9

Musuq wrote:
I calculated the values for each of the substances just to make sure I got the concept, and I got this...



So, Yes, Y will accumulate the most, in number and also b/c it is an spontaneous reaction.

Again Good luck in your exam amitodc2b

sorry i was late in replying, was studying for my exam. thanks so much for ur help. basically everything the letter your calculating will have a reverse sign it looks like?



  #10

hey amit BEST OF LUCK. is ur exam on 31st?

  #11

guys, in exam it takes atleast 5 min to calculate all these ( im poor in maths..) so a simple way... G0 is nothing but the energy needed to produce the reaction. If it is + energy is needed for the reaction to proceed. if it is -ve, then energy is given out or in other words the reaction proceed spontaneously. so the higher the +ve value, the more difficult for the reaction to proceed. so substrate of tht reaction will accumulate.. in the equation Y--->Z needs the most energy +7.7. so at equilibrium Y will accumulate..



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