What is the role of creatine phosphate in muscle energy metabolism?

• A. Acts as a storage form of high-energy phosphate for ATP regeneration.
• B. Provides energy primarily through long-term oxidative metabolism.
• C. Donates a phosphate to ADP to rapidly regenerate ATP during short, high-intensity effort.
• D. Is metabolized to produce ATP directly during sprinting.

Answer: (C)

Creatine phosphate acts as a rapid-energy buffer in muscle by storing a high-energy phosphate group and ready to donate it when needed. During short, high-intensity effort, ATP is consumed quickly, and creatine phosphate donates its phosphate to ADP via the enzyme creatine kinase to rapidly regenerate ATP. This allows muscles to sustain contractions for the initial seconds of intense activity until glycolysis and oxidative phosphorylation take over. While it is indeed a storage form of high-energy phosphate, the essential point is its role in rapid ATP regeneration, not providing energy directly or for long-term metabolism. The oxidative pathway provides energy for longer-duration activities, and creatine phosphate is not used to produce ATP directly during sprinting beyond the rapid phosphate transfer.