A critical reaction in the production of energy to do work or drive chemical rea
ID: 957493 • Letter: A
Question
A critical reaction in the production of energy to do work or drive chemical reactions in biological systems is the hydrolysis of adenosine triphosphate, ATP, to adenosine diphosphate, ADP, as described by ATP(aq) + H_2O(l) right arrow ADP(aq) + HPO^2-_4(aq) for which deltaGdegree_rxn = -30.5 kJ/mol at 37.0 degreeC and pH 7.0. Calculate the value of deltaG_rxn in a biological cell in which [ATP] = 5.0 mM, [ADP] = 0.90 mM, and [HP0^2-_4] = 5.0 mM Is the hydrolysis of ATP spontaneous under these conditions?Explanation / Answer
ANSWER
ATP + H2O -------> ADP + HPO42-
G = Go + RTlnK
R = Gas constant = 8.314J/Kmol
T = absolute temperature = 310K (37 oC)
K = [ADP] [HPO42-] / [ATP]
K = 0.5 mMX 0.9mM / 0.5 mM = 9.0 X 10-4
G = -30500J + 8.314 X 310 ln 9.0 X 10-4
G = - 30500 - 18044.3 = - 48544.3J = - 48.5KJ