PracticeQuestions_Chapter03

PracticeQuestions_Chapter03 - Consider a reaction, X->Y...

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Consider a reaction, X->Y in the cell at 25 o C. At equilibrium, [X] and [Y] are 50 μM and 5 μM, respectively. Using the following equations and what you know, answer the following questions. Δ G= Δ G o ’+1.4logQ (kcal/mol) (logZ is negative if Z<1, positive if Z>1, and 0 when Z=1. For example, log0.01=-2, log0.1=-1, log1=0, log10=1, log100=2). 1. What is the Δ G o ’ for X->Y (hint: at equilibrium, Δ G=0 and Q=K eq )? Is the conversion X->Y favored at standard condition? 2. For a circumstance in which [X] is 100 μM and [Y] is 1 μM. Is conversion of X to Y favorable? How fast the conversion will happen? 3. Suppose that starting conditions in which the reaction X Y is unfavorable. However, the cell needs to produce more Y. Which of the followings cells can do to have the conversion happen? A. Coupling the conversion to a reaction that can make the total free energy change a negative value. B. Reduce [Y] without increasing [X] so that 1.4logQ make the Δ G a negative value. C. Making more enzymes that catalyze the conversion. D. Decreasing Δ G o ’ by stabilizing the transition state between X->Y conversion. 4. Which one or more of the following reactions will NOT occur spontaneously under the standard conditions? A. ADP + Pi ATP Δ G °’ = +7.3 kcal/mole B. glucose-1-phosphate glucose-6-phosphate Δ G °’ = –1.7 kcal/mole C. glucose + fructose sucrose Δ G °’ = +5.5 kcal/mole D. glucose CO2 + H2O Δ G °’ = –686 kcal/mole 5. Any reaction A B is at equilibrium when A. Δ G = 0. B. Δ G °’ = 0. C. [A] = [B]. D. Δ G = Δ G °’. E. both forward and backward rates are zero. 6. Answer the following questions using either increased, decreased, or unchanged. A. If you dissolve sugar into water in a capped bottle, the total entropy of sugar and water in the bottle has _______. B. If you open the cap, water in the bottle will evaporate and sugar molecules will be crystallized eventually. Entropy of the sugar has ________ by crystallization. However, the entropy change of the sugar is compensated by the ___________ entropy by evaporation of the water molecules. 7. Living organisms require a continual supply of energy to exist because they
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This note was uploaded on 11/21/2011 for the course PCB 3134 taught by Professor Multiple during the Fall '08 term at University of Florida.

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PracticeQuestions_Chapter03 - Consider a reaction, X-&gt;Y...

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