High-energy transfer compounds (such as ATP and acetyl-CoA) are characterized by their ability to:
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Aaccept large amounts of free energy
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Btransfer large amounts of free energy
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Cmeasure free energy
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Dnone of the above
Answer
Correct Answer: transfer large amounts of free energy
Explanation
Introduction / Context:High-energy compounds are central to metabolism. They act as energy currency, coupling exergonic and endergonic processes. Recognizing their defining property is crucial for understanding bioenergetics.
Given Data / Assumptions:
- Examples include ATP, GTP, acetyl-CoA, and phosphoenolpyruvate.
- They contain bonds with large negative free energy of hydrolysis.
- Focus is on what they do functionally in pathways.
Concept / Approach:Such molecules transfer free energy to other molecules by group transfer reactions (e.g., phosphoryl transfer from ATP). The large negative ΔG of hydrolysis drives coupled reactions forward.
Step-by-Step Solution:
Identify function: donate phosphoryl or acyl groups.Assess impact: transfer of chemical potential (free energy) to acceptor reactions.Select statement matching this: transfer large amounts of free energy.Verification / Alternative check:Coupling ATP hydrolysis to unfavorable biosyntheses (e.g., aminoacyl-tRNA formation) exemplifies energy transfer.
Why Other Options Are Wrong:Accept large energy: Vague and not the defining feature. Measure free energy: Measurement is an analytical concept, not molecular function. None: Incorrect since a correct description exists.
Common Pitfalls:Misinterpreting “high-energy bond” as a store to be “accepted” rather than transferred in a chemical reaction.
Final Answer:transfer large amounts of free energy