Concept explainers
(a)
Interpretation:
The equation for the coupled reaction of 3-phosphoglycerate with ATP to form 1,3-bisphosphoglycerate and ADP should be written.
Concept Introduction:
Phosphorylation of 1,3-bisphosphoglycerate is an energetically unfavorable reaction. By coupling with the ATP hydrolysis, this reaction can be converted to a favorable state.
Answer to Problem 23.34P
Explanation of Solution
The conversion of 1,3-bisphosphatoglycerate to 3-phosphoglycerate and hydrogen phosphate can be represented as follows:
Similarly, the conversion of ATP to ADP can be represented as follows:
To cancel the common species and to get the desired reaction, reaction (2) should be added to the reverse of reaction (1).
The coupled reaction can be represented as follows:
(b)
Interpretation:
The energy change for this coupled reaction should be calculated.
Concept Introduction:
Phosphorylation of 1,3-bisphosphoglycerate is an energetically unfavorable reaction. by coupling with the ATP hydrolysis, this reaction can be converted to a favorable state.
In the hydrolysis of ATP breaks one phosphate group, forming ADP and hydrogen phosphate, This reaction releases 7.3 kcal/mol of energy.
When the energy of a reaction is a positive value, that reaction is an endothermic reaction and it requires the energy of surrounding to complete the reaction.
When the energy of a reaction is a negative value, that reaction is exothermic, and it releases energy by acting as an energetically favorable reaction.
Answer to Problem 23.34P
- 4.5 kcal/mol
Explanation of Solution
The conversion of 1,3-bisphosphatoglycerate to 3-phosphoglycerate and hydrogen phosphate can be represented as follows:
The energy for the above reaction is
Similarly, the conversion of ATP to ADP can be represented as follows:
The energy for the above reaction is
To cancel the common species and to get the desired reaction, reaction (2) should be added to the reverse of reaction (1).
The coupled reaction can be represented as follows:
Thus, the energy change for the reaction is
(c)
Interpretation:
Whether this reaction is used to synthesize ATP from ADP should be explained.
Concept Introduction:
The reaction releases 7.3 kcal/mol of energy.
When the energy of a reaction is a positive value, that reaction is an endothermic reaction and it requires the energy of surrounding to complete the reaction.
When the energy of a reaction is a negative value, that reaction is exothermic, and it releases energy by acting as an energetically favorable reaction.
Answer to Problem 23.34P
Unfavorable
Explanation of Solution
Energy = 11.8 kcal/mol − 7.3 kcal/mol = 4.5 kcal/mol
When the energy of a reaction is a positive value, that reaction is an endothermic reaction and it requires the energy of surrounding to complete the reaction.
Therefore, the reaction is unfavorable.
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Chapter 23 Solutions
EBK GENERAL, ORGANIC, & BIOLOGICAL CHEM
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