Multiple Choice
In the context of Gibbs free energy, when ATP is hydrolyzed (loses a terminal phosphate group to form ADP and inorganic phosphate), what is released that can be used to drive cellular work?
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1. Introduction to Biochemistry
Gibbs Free Energy
Multiple Choice
In the context of Gibbs free energy and ATP hydrolysis, where is most of the usable free energy of ATP primarily associated?
A
In the electrostatic repulsion and resonance stabilization differences associated with the phosphoanhydride bonds between the phosphate groups
B
In the ribose sugar via oxidation of its hydroxyl groups during ATP hydrolysis
C
In the adenine base through aromatic ring electron delocalization that is released upon hydrolysis
D
In the terminal phosphate because breaking any chemical bond directly releases energy regardless of products
Verified step by step guidance1
Understand that Gibbs free energy change (ΔG) in ATP hydrolysis reflects the difference in free energy between reactants and products, not simply the energy required to break bonds.
Recognize that ATP contains phosphoanhydride bonds between its phosphate groups, which are high-energy bonds due to electrostatic repulsion between negatively charged phosphate groups.
Consider that upon hydrolysis, the products (ADP and inorganic phosphate) are stabilized by resonance and reduced electrostatic repulsion, which contributes to the overall negative ΔG.
Note that the energy is not stored in the ribose sugar or adenine base, as these parts do not undergo significant energetic changes during hydrolysis.
Conclude that the usable free energy primarily comes from the differences in electrostatic repulsion and resonance stabilization associated with the phosphoanhydride bonds, rather than the act of bond breaking itself.
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