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Exam 2: Practice problems Chem4400 1. The protein Sre is a signaling molecule that is phosphory lated by acetyl phosphate and dephosphorylated by hydrolysis. Thus, Sre catalyzes the acetyl-phosphate hydrolysis reaction: (1) CH3CO-Pi (aq) + H20 (l)-→ CH3COOH (aq) + P (a) AG--40. Ik/ / mol As with many biochemical reactions, phosphorylation is driven by ATP hydrolysis: (2) ATP(aq) + H2O (/) → ADP (aq) + P, (ag) Cellular concentrations of the relevant species are: [ATP] [ADP] [Pl 1 mM; [CHsCO-P] 0.1 mM: [CH3COOH-10.0 mM. You can assume that the activity coefficients are 1 . (a) Write an expression of K for reaction I. (b) Calculate ΔG, for reaction 1 at cellular concentrations, 25°C, pH 7.0, and 1 bar. (c) Calculate ΔG, for reaction 2 at the same conditions. Can reaction 2 spontaneously drive the reverse of reaction 1? (d) Even though the hydrolysis of ATP drives many biochemical reactions, the phosphate bond is not a thermodynamically anomalous bond. Give 2 reasons why the ATP hydrolysis reaction is such a favorable reaction.

The protein Src is a signaling molecule that is phosphorylated by acetyl phosphate and dephosphorylated by hydrolysis. Thus, Src catalyzes the acetyl-phosphate hydrolysis reaction:

PICTURE. Please answer all the problems and explain.

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Answer #1

Eta,3.by,umLondont [cちco m] [p.3 ,o = conc 100MM l00 Mohan Cha너 -57b5.SY x t-ı)寸1-1(d)

Reason 1 : - products of hydrolysis (ADP +Pi) are more stablethan reactant(ATP) due to the presence of resonance stabilization.which means ADP have more resonance forms than ATP.

Reason 2 :- ADP molecule don't have as many negative charge in close proximity as ATP and due to loss of one inorganic phosphate,ADP is better solvated by water.  

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