Energy Conversion Problem 1. a) Influence of concentration on the free energy change. In frog muscle, the concentrations of ATP, ADP, and phosphate are 1.25x10-³ M, 0.50x10-3 M, and 2.50 x10-3 M respectively. Write the reaction and the reaction quotient, Q, for the reaction ATP → ADP + P₁. Calculate the free energy change, AG', for the hydrolysis of ATP in muscle cells given the concentrations given above. Assume that AG"=-31.0 kJ mol-¹ for the hydrolysis of ATP, the temperature is 25°C, and the pH=7. b) For this system, what is the maximum amount of work that can be done per mole of ATP hydrolyzed? c) In muscle, phosphocreatine serves as a carrier of chemical energy. It can transfer its phosphate group to ADP to replenish the ATP used in muscle contraction. This is an example of energy coupling - using the energy of a very favorable reaction to drive an unfavorable reaction. The enzyme creatine phosphokinase catalyzes the reaction: creatine phosphokinase Net rxn creatine + ATP AG"= ???? kJ mol-¹ phosphocreatine + ADP d) Show above how you calculate AG" for the net reaction given that the hydrolysis for phosphocreatine (Phosphocreatine → creatine + Pi) is AG"=-43.1 kJ mol-¹.
Energy Conversion Problem 1. a) Influence of concentration on the free energy change. In frog muscle, the concentrations of ATP, ADP, and phosphate are 1.25x10-³ M, 0.50x10-3 M, and 2.50 x10-3 M respectively. Write the reaction and the reaction quotient, Q, for the reaction ATP → ADP + P₁. Calculate the free energy change, AG', for the hydrolysis of ATP in muscle cells given the concentrations given above. Assume that AG"=-31.0 kJ mol-¹ for the hydrolysis of ATP, the temperature is 25°C, and the pH=7. b) For this system, what is the maximum amount of work that can be done per mole of ATP hydrolyzed? c) In muscle, phosphocreatine serves as a carrier of chemical energy. It can transfer its phosphate group to ADP to replenish the ATP used in muscle contraction. This is an example of energy coupling - using the energy of a very favorable reaction to drive an unfavorable reaction. The enzyme creatine phosphokinase catalyzes the reaction: creatine phosphokinase Net rxn creatine + ATP AG"= ???? kJ mol-¹ phosphocreatine + ADP d) Show above how you calculate AG" for the net reaction given that the hydrolysis for phosphocreatine (Phosphocreatine → creatine + Pi) is AG"=-43.1 kJ mol-¹.
Biochemistry
9th Edition
ISBN:9781319114671
Author:Lubert Stryer, Jeremy M. Berg, John L. Tymoczko, Gregory J. Gatto Jr.
Publisher:Lubert Stryer, Jeremy M. Berg, John L. Tymoczko, Gregory J. Gatto Jr.
Chapter1: Biochemistry: An Evolving Science
Section: Chapter Questions
Problem 1P
Related questions
Question
Please show all work/answers for the question
![Energy Conversion Problem
1. a) Influence of concentration on the free energy change. In frog muscle, the concentrations of ATP, ADP,
and phosphate are 1.25x10-³ M, 0.50x10-³ M, and 2.50 x10³ M respectively. Write the reaction and the
reaction quotient, Q, for the reaction ATP → ADP + P₁. Calculate the free energy change, AG', for the hydrolysis
of ATP in muscle cells given the concentrations given above. Assume that AGº'=-31.0 kJ mol-¹ for the hydrolysis
of ATP, the temperature is 25°C, and the pH=7.
b) For this system, what is the maximum amount of work that can be done per mole of ATP hydrolyzed?
c) In muscle, phosphocreatine serves as a carrier of chemical energy. It can transfer its phosphate group to
ADP to replenish the ATP used in muscle contraction. This is an example of energy coupling - using the
energy of a very favorable reaction to drive an unfavorable reaction. The enzyme creatine phosphokinase
catalyzes the reaction:
Net rxn
phosphocreatine + ADP
creatine phosphokinase
→
creatine + ATP
AG°= ???? kJ mol-¹
d) Show above how you calculate AG" for the net reaction given that the hydrolysis for phosphocreatine
(Phosphocreatine → creatine + Pi) is AGº'=-43.1 kJ mol-¹.
e) Write the equilibrium constant expression and calculate the equilibrium constant of this reaction using
AG⁹¹.
f) As ATP is used, the phosphocreatine stores are depleted. Using the ATP and ADP concentrations given above
in part a, at what ratio of [creatine]/[phosphocreatine] would you expect the reaction to stop (or reach
equilibrium)? Use K from e) and the equilibrium constant expression to solve this problem.
g) Do some research. How does the level of phosphocreatine remain high in muscle cells. Where/how is it
remade from creatine? Look at the enzyme that carries out this reaction. What does it require? How does it
facilitate the coupled reaction? (one paragraph)](/v2/_next/image?url=https%3A%2F%2Fcontent.bartleby.com%2Fqna-images%2Fquestion%2Fc687de40-2a04-4618-94c5-bffabbb64b83%2Fee22a515-4cea-4d86-99d7-c67ca6a50811%2F7vxn3a5_processed.jpeg&w=3840&q=75)
Transcribed Image Text:Energy Conversion Problem
1. a) Influence of concentration on the free energy change. In frog muscle, the concentrations of ATP, ADP,
and phosphate are 1.25x10-³ M, 0.50x10-³ M, and 2.50 x10³ M respectively. Write the reaction and the
reaction quotient, Q, for the reaction ATP → ADP + P₁. Calculate the free energy change, AG', for the hydrolysis
of ATP in muscle cells given the concentrations given above. Assume that AGº'=-31.0 kJ mol-¹ for the hydrolysis
of ATP, the temperature is 25°C, and the pH=7.
b) For this system, what is the maximum amount of work that can be done per mole of ATP hydrolyzed?
c) In muscle, phosphocreatine serves as a carrier of chemical energy. It can transfer its phosphate group to
ADP to replenish the ATP used in muscle contraction. This is an example of energy coupling - using the
energy of a very favorable reaction to drive an unfavorable reaction. The enzyme creatine phosphokinase
catalyzes the reaction:
Net rxn
phosphocreatine + ADP
creatine phosphokinase
→
creatine + ATP
AG°= ???? kJ mol-¹
d) Show above how you calculate AG" for the net reaction given that the hydrolysis for phosphocreatine
(Phosphocreatine → creatine + Pi) is AGº'=-43.1 kJ mol-¹.
e) Write the equilibrium constant expression and calculate the equilibrium constant of this reaction using
AG⁹¹.
f) As ATP is used, the phosphocreatine stores are depleted. Using the ATP and ADP concentrations given above
in part a, at what ratio of [creatine]/[phosphocreatine] would you expect the reaction to stop (or reach
equilibrium)? Use K from e) and the equilibrium constant expression to solve this problem.
g) Do some research. How does the level of phosphocreatine remain high in muscle cells. Where/how is it
remade from creatine? Look at the enzyme that carries out this reaction. What does it require? How does it
facilitate the coupled reaction? (one paragraph)
Expert Solution
Step 1: 1(a)
For the chemical reaction:
aA + bB -> cC + dD
The reaction quotient Q is calculated as:
Q = ([C]^c * [D]^d) / ([A]^a * [B]^b)
So, for ATP hydrolysis reaction,
Q= [ ADP] *[Pi]/[ ATP]
From Thermodynamics, equation relating ΔG’ to standard ΔG°’ is given by
ΔG’ = ΔG°’ + RT lnQ
Given temperature = 25°C = 298K
ΔG’ = ( -31000 + 8.314*298*ln ((0.5*10-3) (2.5*10-3)/1.25*10-3)) J/mol
= -48,114.46 J/mol
Step by step
Solved in 4 steps with 1 images
Recommended textbooks for you
Biochemistry
Biochemistry
ISBN:
9781319114671
Author:
Lubert Stryer, Jeremy M. Berg, John L. Tymoczko, Gregory J. Gatto Jr.
Publisher:
W. H. Freeman
Lehninger Principles of Biochemistry
Biochemistry
ISBN:
9781464126116
Author:
David L. Nelson, Michael M. Cox
Publisher:
W. H. Freeman
Fundamentals of Biochemistry: Life at the Molecul…
Biochemistry
ISBN:
9781118918401
Author:
Donald Voet, Judith G. Voet, Charlotte W. Pratt
Publisher:
WILEY
Biochemistry
Biochemistry
ISBN:
9781319114671
Author:
Lubert Stryer, Jeremy M. Berg, John L. Tymoczko, Gregory J. Gatto Jr.
Publisher:
W. H. Freeman
Lehninger Principles of Biochemistry
Biochemistry
ISBN:
9781464126116
Author:
David L. Nelson, Michael M. Cox
Publisher:
W. H. Freeman
Fundamentals of Biochemistry: Life at the Molecul…
Biochemistry
ISBN:
9781118918401
Author:
Donald Voet, Judith G. Voet, Charlotte W. Pratt
Publisher:
WILEY
Biochemistry
Biochemistry
ISBN:
9781305961135
Author:
Mary K. Campbell, Shawn O. Farrell, Owen M. McDougal
Publisher:
Cengage Learning
Biochemistry
Biochemistry
ISBN:
9781305577206
Author:
Reginald H. Garrett, Charles M. Grisham
Publisher:
Cengage Learning
Fundamentals of General, Organic, and Biological …
Biochemistry
ISBN:
9780134015187
Author:
John E. McMurry, David S. Ballantine, Carl A. Hoeger, Virginia E. Peterson
Publisher:
PEARSON