Chapter 23, Problem 32P

Interpretation Introduction

(a)

Interpretation:

The balance coupled chemical equation for the coupled reaction of 3-phosphoglycerate with ATP to form 1,3-bisphosphoglycerate and ADP with the help of given reaction equations needs to be determined.

  $\begin{array}{l}{\text{1,3-bisphosphoglycerate + H}}_{\text{2}}\text{O }\stackrel{}{\to }{\text{ 3-phosphoglycerate + HPO}}_{\text{4}}{}^{\text{2-}}\text{ Energy change = -11}\text{.8 kcal/mol}\mathrm{.....}\text{(1)}\\ {\text{ATP + H}}_{\text{2}}\text{O }\stackrel{}{\to }{\text{ ADP + HPO}}_{\text{4}}{}^{\text{2-}}\text{ Energy change = -7}\text{.3 kcal/mol}\mathrm{......}\end{array}$

Concept Introduction:

Born- Haber cycle is used to compute the lattice energy of ionic compounds. Lattice energy can be defined as the energy that is needed to break a compound to its constituent's elements. It can also defined as the energy released during the formation of ionic compounds from its constituent elements. It is based on the Hess law. The Hess law states that the enthalpy change for multistep chemical reaction is the sum of all enthalpy changes. It can be written as;

  $\sum \Delta {\text{H}}_{\text{reaction}}\text{ =}\Delta \text{H1 + }\Delta \text{H2+}\Delta \text{H3}\mathrm{....}$

Answer to Problem 32P

  $\text{3-phosphoglycerate + ATP }\stackrel{}{\to }\text{ 1,3-bisphosphoglycerate + ADP}$

Explanation of Solution

Given:

  $\begin{array}{l}{\text{1,3-bisphosphoglycerate + H}}_{\text{2}}\text{O }\stackrel{}{\to }{\text{ 3-phosphoglycerate + HPO}}_{\text{4}}{}^{\text{2-}}\text{ Energy change = -11}\text{.8 kcal/mol}\mathrm{.....}\text{(1)}\\ {\text{ATP + H}}_{\text{2}}\text{O }\stackrel{}{\to }{\text{ ADP + HPO}}_{\text{4}}{}^{\text{2-}}\text{ Energy = -7}\text{.3 kcal/mol}\end{array}$

To get equation for the coupled reaction of 3-phosphoglycerate with ATP to form 1,3-bisphosphoglycerate and ADP, reverse the equation (1) and add it with (2):

  $\begin{array}{l}{\text{3-phosphoglycerate + HPO}}_{\text{4}}{}^{\text{2-}}\stackrel{}{\to }{\text{ 1,3-bisphosphoglycerate + H}}_{\text{2}}\text{O Energy change = +11}\text{.8 kcal/mol}\mathrm{.....}\text{(1)}\\ {\text{ATP + H}}_{\text{2}}\text{O }\stackrel{}{\to }{\text{ ADP + HPO}}_{\text{4}}{}^{\text{2-}}\text{ Energy change = + 7}\text{.3 kcal/mol}\mathrm{......}\text{(2)}\\ \text{\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_}\\ \text{3-phosphoglycerate + ATP }\stackrel{}{\to }\text{ 1,3-bisphosphoglycerate + ADP}\mathrm{.....}\text{(3)}\end{array}$

Hence the coupled equation must be:

  $\text{3-phosphoglycerate + ATP }\stackrel{}{\to }\text{ 1,3-bisphosphoglycerate + ADP}$

Interpretation Introduction

(b)

Interpretation:

The energy change for the balance coupled reaction of 3-phosphoglycerate with ATP to form 1,3-bisphosphoglycerate and ADP with the help of given reaction equations needs to be determined. $\begin{array}{l}{\text{1,3-bisphosphoglycerate + H}}_{\text{2}}\text{O }\stackrel{}{\to }{\text{ 3-phosphoglycerate + HPO}}_{\text{4}}{}^{\text{2-}}\text{ Energy change = -11}\text{.8 kcal/mol}\mathrm{.....}\text{(1)}\\ {\text{ATP + H}}_{\text{2}}\text{O }\stackrel{}{\to }{\text{ ADP + HPO}}_{\text{4}}{}^{\text{2-}}\text{ Energy change = -7}\text{.3 kcal/mol}\mathrm{......}\text{(2)}\end{array}$

Concept Introduction:

Born- Haber cycle is used to compute the lattice energy of ionic compounds. Lattice energy can be defined as the energy that is needed to break a compound to its constituent's elements. It can also defined as the energy released during the formation of ionic compounds from its constituent elements. It is based on the Hess law. The Hess law states that the enthalpy change for multistep chemical reaction is the sum of all enthalpy changes. It can be written as;

  $\sum \Delta {\text{H}}_{\text{reaction}}\text{ =}\Delta \text{H1 + }\Delta \text{H2+}\Delta \text{H3}\mathrm{....}$

Answer to Problem 32P

  $\text{3-phosphoglycerate + ATP }\stackrel{}{\to }\text{ 1,3-bisphosphoglycerate + ADP ; energy change = + 4}\text{.5 kcal/mol }$

Explanation of Solution

Given:

  $\begin{array}{l}{\text{1,3-bisphosphoglycerate + H}}_{\text{2}}\text{O }\stackrel{}{\to }{\text{ 3-phosphoglycerate + HPO}}_{\text{4}}{}^{\text{2-}}\text{ Energy change = -11}\text{.8 kcal/mol}\mathrm{.....}\text{(1)}\\ {\text{ATP + H}}_{\text{2}}\text{O }\stackrel{}{\to }{\text{ ADP + HPO}}_{\text{4}}{}^{\text{2-}}\text{ Energy = -7}\text{.3 kcal/mol}\end{array}$

To get equation for the coupled reaction of 13-phosphoglycerate with ATP to form 1,3-bisphosphoglycerate and ADP, reverse the equation (1) and add it with (2):

  $\begin{array}{l}{\text{3-phosphoglycerate + HPO}}_{\text{4}}{}^{\text{2-}}\stackrel{}{\to }{\text{ 1,3-bisphosphoglycerate + H}}_{\text{2}}\text{O Energy change = +11}\text{.8 kcal/mol}\mathrm{.....}\text{(1)}\\ {\text{ATP + H}}_{\text{2}}\text{O }\stackrel{}{\to }{\text{ ADP + HPO}}_{\text{4}}{}^{\text{2-}}\text{ Energy change = + 7}\text{.3 kcal/mol}\mathrm{......}\text{(2)}\\ \text{\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_}\\ \text{3-phosphoglycerate + ATP }\stackrel{}{\to }\text{ 1,3-bisphosphoglycerate + ADP}\mathrm{.....}\text{(3)}\\ \text{Energy change = + 11}\text{.8 kcal/mol -7}\text{.3kcal/mol}\\ \text{ Energy change = +4}\text{.5 kcal/mol }\end{array}$

Interpretation Introduction

(c)

Interpretation:

The possibility of given coupled reaction to be energetically favorable needs to be explained. $\begin{array}{l}{\text{1,3-bisphosphoglycerate + H}}_{\text{2}}\text{O }\stackrel{}{\to }{\text{ 3-phosphoglycerate + HPO}}_{\text{4}}{}^{\text{2-}}\text{ Energy change = -11}\text{.8 kcal/mol}\mathrm{.....}\text{(1)}\\ {\text{ATP + H}}_{\text{2}}\text{O }\stackrel{}{\to }{\text{ ADP + HPO}}_{\text{4}}{}^{\text{2-}}\text{ Energy change = -7}\text{.3 kcal/mol}\mathrm{......}\text{(2)}\end{array}$

Concept Introduction:

Born- Haber cycle is used to compute the lattice energy of ionic compounds. Lattice energy can be defined as the energy that is needed to break a compound to its constituent's elements. It can also defined as the energy released during the formation of ionic compounds from its constituent elements. It is based on the Hess law. The Hess law states that the enthalpy change for multistep chemical reaction is the sum of all enthalpy changes. It can be written as;

  $\sum \Delta {\text{H}}_{\text{reaction}}\text{ =}\Delta \text{H1 + }\Delta \text{H2+}\Delta \text{H3}\mathrm{....}$

Answer to Problem 32P

  $\text{3-phosphoglycerate + ATP }\stackrel{}{\to }\text{ 1,3-bisphosphoglycerate + ADP ; energy change = + 4}\text{.5 kcal/mol }$

The given reaction is not energetically favorable.

Explanation of Solution

  $\begin{array}{l}{\text{3-phosphoglycerate + HPO}}_{\text{4}}{}^{\text{2-}}\stackrel{}{\to }{\text{ 1,3-bisphosphoglycerate + H}}_{\text{2}}\text{O Energy change = +11}\text{.8 kcal/mol}\mathrm{.....}\text{(1)}\\ {\text{ATP + H}}_{\text{2}}\text{O }\stackrel{}{\to }{\text{ ADP + HPO}}_{\text{4}}{}^{\text{2-}}\text{ Energy change = + 7}\text{.3 kcal/mol}\mathrm{......}\text{(2)}\\ \text{\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_}\\ \text{3-phosphoglycerate + ATP }\stackrel{}{\to }\text{ 1,3-bisphosphoglycerate + ADP}\mathrm{.....}\text{(3) Energy change = +4}\text{.5 kcal/mol }\end{array}$

Since the energy change for the formation of ADP from ATP is energetically not favored because the energy change is positive.