Energy metabolism — Which mineral is centrally involved in enzyme-controlled, energy-yielding reactions of metabolism (for example, high-energy phosphate transfer and phosphorylation)?
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ACalcium
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BPhosphorus
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CIron
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DCopper
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ESodium
Answer
Correct Answer: Phosphorus
Explanation
Introduction / Context:Energy metabolism depends on the transfer of phosphate groups and the storage of energy in high-energy phosphate bonds. Phosphorus, present in ATP, ADP, AMP, creatine phosphate, and phosphorylated intermediates, is fundamental to these enzyme-controlled energy-yielding reactions.
Given Data / Assumptions:
- ATP/ADP cycling underlies cellular energy economy.
- Phosphorylation/dephosphorylation regulate key enzymes and pathways.
- Metabolic intermediates (e.g., glucose-6-phosphate) contain phosphate groups derived from cellular phosphorus pools.
Concept / Approach:Identify the mineral whose chemical form directly constitutes the energy currency and regulatory modifications. While magnesium is a ubiquitous cofactor stabilizing ATP, the question emphasizes the phosphate-based chemistry driving energy yield, which directly implicates phosphorus.
Step-by-Step Solution:
Recognize ATP as adenosine triphosphate → phosphorus-rich molecule.Note phosphorylation controls glycolysis, glycogen metabolism, and oxidative pathways.Conclude that phosphorus is central to energy-yielding reactions.Verification / Alternative check:Biochemical pathways universally depict phosphate transfers as the core of energy handling, confirming phosphorus’s centrality.
Why Other Options Are Wrong:
a) Calcium is signaling/clotting; not the primary energy-transfer atom.c) Iron participates in electron transfer, not phosphate-bond energy storage.d) Copper functions in oxidases and iron handling.e) Sodium is important for gradients and nerve impulses, not phosphate energy chemistry.Common Pitfalls:Confusing magnesium’s role in stabilizing ATP with phosphorus’s role as the energy-bearing phosphate group.
Final Answer:Phosphorus.