Chapter 15, Problem 15P

Interpretation Introduction

(a)

Interpretation:

The direction of the reversible reaction between ATP and creatine is to be stated.

Concept introduction:

A thermodynamic potential that is utilized in the calculation of the highest reversible function taking place in the thermodynamic system at the constant value pressure and temperature is known as Gibbs-free energy. It is denoted by $\Delta G°$.

Answer to Problem 15P

The reversible reaction between ATP and creatine moves towards the left side of the reaction.

Explanation of Solution

The given reversible reaction is given below.

$\text{ATP}+\text{creatine}\rightleftharpoons \text{creatine}\text{phosphate}+\text{ADP}$.

The standard Gibbs free energy for the conversion of ATP to ADP is $\Delta G°\text{'}=-7.3\text{kcal}{\text{mol}}^{-1}$.

The given standard Gibbs free energy for the conversion of creatine to creatine phosphate is $\Delta G°\text{'}=-10.3\text{kcal}{\text{mol}}^{-1}$.

Thus, the change in the standard Gibbs free energy for the conversions is calculated as follows.

$\begin{array}{c}\text{Change}\text{in}\Delta G°\text{'}=\Delta G°\text{'}\text{ for}\text{ATP}\text{to}\text{ADP}-\Delta G°\text{'}\text{ for}\text{creatine to creatine phosphate}\\ \Delta G°\text{'}=7.3\text{kcal}{\text{mol}}^{-1}-10.3\text{kcal}{\text{mol}}^{-1}\\ =-3\text{kcal}{\text{mol}}^{-1}\end{array}$

Thus, the value of the Gibbs free energy is $-3\text{kcal}{\text{mol}}^{-1}$. The negative value of Gibbs free energy indicates that reaction moves in the left hand side.

Interpretation Introduction

(b)

Interpretation:

The direction of the reversible reaction between ATP and glycerol is to be stated.

Concept introduction:

A thermodynamic potential that is utilized in the calculation of the highest reversible function taking place in the thermodynamic system at the constant value pressure and temperature is known as Gibbs-free energy. It is denoted by $\Delta G°$.

Answer to Problem 15P

The reversible reaction between ATP and glycerol moves towards the right side of the reaction.

Explanation of Solution

The given reversible reaction is given below.

$\text{ATP}+\text{glycerol}\rightleftharpoons \text{glycerol}3-\text{phosphate}+\text{ADP}$.

The standard Gibbs free energy for the conversion of ATP to ADP is $\Delta G°\text{'}=-7.3\text{kcal}{\text{mol}}^{-1}$.

The given standard Gibbs free energy for the conversion of glycerol to glycerol 3-phosphate is $\Delta G°\text{'}=-2.2\text{kcal}{\text{mol}}^{-1}$.

Thus, the change in the standard Gibbs free energy for the conversions is calculated as follows.

$\begin{array}{c}\text{Change}\text{in}\Delta G°\text{'}=\Delta G°\text{'}\text{ for}\text{ATP}\text{to}\text{ADP}-\Delta G°\text{'}\text{ for}\text{glycerol to glycerol}3-\text{phosphate}\\ \Delta G°\text{'}=7.3\text{kcal}{\text{mol}}^{-1}-2.2\text{kcal}{\text{mol}}^{-1}\\ =5.1\text{kcal}{\text{mol}}^{-1}\end{array}$

Thus, the value of the Gibbs free energy is $5.1\text{kcal}{\text{mol}}^{-1}$. The positive value of Gibbs free energy indicates that reaction moves in the right hand side.

Interpretation Introduction

(c)

Interpretation:

The direction of the reversible reaction between ATP and pyruvate is to be stated.

Concept introduction:

A thermodynamic potential that is utilized in the calculation of the highest reversible function taking place in the thermodynamic system at the constant value pressure and temperature is known as Gibbs-free energy. It is denoted by $\Delta G°$.

Answer to Problem 15P

The reversible reaction between ATP and pyruvate moves towards the left side of the reaction.

Explanation of Solution

The given reversible reaction is given below.

$\text{ATP}+\text{pyruvate}\rightleftharpoons \text{phosphoenolpyruvate}+\text{ADP}$.

The standard Gibbs free energy for the conversion of ATP to ADP is $\Delta G°\text{'}=-7.3\text{kcal}{\text{mol}}^{-1}$.

The given standard Gibbs free energy for the conversion of pyruvate to phosphoenolpyruvate is $\Delta G°\text{'}=-14.8\text{kcal}{\text{mol}}^{-1}$.

Thus, the change in the standard Gibbs free energy for the conversions is calculated as follows.

$\begin{array}{c}\text{Change}\text{in}\Delta G°\text{'}=\Delta G°\text{'}\text{ for}\text{ATP}\text{to}\text{ADP}-\Delta G°\text{'}\text{ for}\text{pyruvate to phosphoenolpyruvate}\\ \Delta G°\text{'}=7.3\text{kcal}{\text{mol}}^{-1}-14.8\text{kcal}{\text{mol}}^{-1}\\ =-7.5\text{kcal}{\text{mol}}^{-1}\end{array}$

Thus, the value of the Gibbs free energy is $-7.5\text{kcal}{\text{mol}}^{-1}$. The negative value of Gibbs free energy indicates that reaction moves in the left hand side.

Interpretation Introduction

(d)

Interpretation:

The direction of the reversible reaction between ATP and glucose is to be stated.

Concept introduction:

A thermodynamic potential that is utilized in the calculation of the highest reversible function taking place in the thermodynamic system at the constant value pressure and temperature is known as Gibbs-free energy. It is denoted by $\Delta G°$.

Answer to Problem 15P

The reversible reaction between ATP and glucose moves towards the right side of the reaction.

Explanation of Solution

The given reversible reaction is given below.

$\text{ATP}+\text{glucose}\rightleftharpoons \text{glucose}6-\text{phosphate}+\text{ADP}$.

The standard Gibbs free energy for the conversion of ATP to ADP is $\Delta G°\text{'}=-7.3\text{kcal}{\text{mol}}^{-1}$.

The given standard Gibbs free energy for the conversion of glucose to glucose6-phosphate is $\Delta G°\text{'}=-3.3\text{kcal}{\text{mol}}^{-1}$.

Thus, the change in the standard Gibbs free energy for the conversions is calculated as follows.

$\begin{array}{c}\text{Change}\text{in}\Delta G°\text{'}=\Delta G°\text{'}\text{ for}\text{ATP}\text{to}\text{ADP}-\Delta G°\text{'}\text{ for}\text{glucose to glucose }6-\text{phosphate}\\ \Delta G°\text{'}=7.3\text{kcal}{\text{mol}}^{-1}-3.3\text{kcal}{\text{mol}}^{-1}\\ =4\text{kcal}{\text{mol}}^{-1}\end{array}$

Thus, the value of the Gibbs free energy is $4\text{kcal}{\text{mol}}^{-1}$. The positive value of Gibbs free energy indicates that reaction moves in the right-hand side.