reaction below might be a suitable coupled reaction to provide the energy for wh
ID: 191380 • Letter: R
Question
reaction below might be a suitable coupled reaction to provide the energy for which of the following reactions (A-E) Explain your choice. (3pts) phosphocreatine + Hz creatine + Pi AG -10.3 kcal/mol G+14.8 keal/mol 9" _ +7.3 kcal mol Gar-+1 1.8 kcal mol AG- 5 kcal/mol A. B. Pyruvate + Pit phosphoenolpyruvate + H2O ADP + Pi ATP + H2O C. D. 3-phosphoglycerate + Pi 1,3-bisphospboglycerate + H2O Malate + NAD. oxaloacetate +NADH + H. +7.1 kcalmol E. Glucose-1-phosphate+ H2O glucose + Pi 9. A) Using the information from problem #9, write the equation for the hydrolysis of ATP (1pt) (1pt). B) Determine&G..; for the hydrolvsisotATe (see info, in problem C) The actual concentrations of ATP, ADP, and Pi differ with cell type ATP (mM) ADP (mM) P.( as shown below. Consequently, the release of free eneray with the hydrolysis of ATP will vary with cell type. Calculate the AG' for the Liver hydrolysis of ATP in muscle, liver, and brain cells (assume 25 C and Muscle express your answer to 3 sig.figs). In which cell type is the free energy of ATP hydrolysis greatest? (4 pts) 3.5 8.0 2.6 1.8 0.9 0.7 5.0 8.0 2.7 BrainExplanation / Answer
The reaction proposed gives 10.3 kcal/mol of energy for another reaction, it is a negative value of Delta G, this means that there is free energy after the reaction.
The reactions in A, B, C and D need energy, E doesn´t, so this one gets discarded.
10.3 kcal/mol is enough energy for B and D, which only need 7.3 and 7.1kcal/mol, the answer could be any of these two. However, the B reaction needs one Pi, which is one of the products of the reaction of the problem, so it can be coupled best with reaction B.
9A) The hydrolisis of ATP is the inverse of reaction B so:
ATP + H2O --> ADP + Pi
9B) the energy of Gibbs or Delta G is the same than in the opposite reaction but with the opposite sign, so instead of needing energy, it releases energy, the same amount, so:
G= -7.3 kcal/mol
9C)
We use the formula:
G= G° + RTln(ADP*Pi/ATP)
Where G° is the original value 7.3kcal/mol
R is the gas constant: 0.00198 kcal/mol
T is the temperature in Kelvin (°C+273) = 25 + 273 = 298
ADP, Pi and ATP should be expressed in M, so instead of 3.5mM of ATP is 0.0035M (1M=1000mM).
So for liver we have a G of -10.82, for muscle -11.44 and for brain -11.56. In brain cells the release of energy is greater.
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