ATP hydrolysis is used as an energy source in biological systems. This reaction

Question

ATP hydrolysis is used as an energy source in biological systems. This reaction (see below) has an associated AG value of -30.5 kJ/mol. ATP4(aq) + H2O(l)-ADP(aq) + H2PO4(aq) a) Calculate the equilibrium constant (KEo) for this reaction at 25°C. (R 8.314462/Kmol) b) Assuming that all of the free energy from the oxidation of glucose (C,H 1206,reaction provided below) was used to form ATP, calculate the number of ATP molecules that could be produced from the oxidation of one glucose molecule. Note that this has to be an integer-if your calculation provides a fractional value, round to the nearest smaller integer (e.g. a value of 22.73 would be rounded to 22, since fractions of molecules don't exist) C6H13O6(s) + 602(g)6CO2(g) + 6H20(1) The free energies of formation of C,H 120%(s), CO2(g), and H200) from their elements in their standard states are -911,-394, and-237 kJ/mol, respectively.

Explanation / Answer

(a)

Using the following relation between dG and K:

dG = -R*T*ln(K)

Putting values:

-30500 = -8.314*298*ln(K)

Solving we get:

K = 2.22*105

(b)

Reaction taking place is:

C6H12O6 + 6O2 ---> 6CO2 + 6H2O

dGrxn = dGf(prod) - dGf(reac)

dGf(prod) = 6*dGf(CO2) + 6*dGf(H2O) = -394*6 + (-237*6) = -3786 kJ

dGf(reac) = 6*dGf(O2) + dGf(glucose) = 0*6 + (-911) = -911 kJ

So,

dG(rxn) = (-3786)-(-911) = -2875 kJ

Number of ATP molecules produced = dGrxn/dG for one molecule ATP = (-2875)/(-30.5) = 94.26

Thus the correct answer is 94

Hope this helps !

Related Questions

Navigate

• Browse (All)
• Browse A
• Subjects

---

---

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.