Creatine phosphate serves to rapidly regenerate ATP by donating a phosphate to ADP. Which statement best describes this role?

• A. Creatine phosphate converts glucose to lactate.
• B. Creatine phosphate donates a phosphate to ADP to form ATP.
• C. Creatine phosphate directly supplies energy without ATP.
• D. Creatine phosphate is produced from ATP and glucose.

Answer: (D)

The main idea is the immediate energy buffer system in muscle, where a high-energy phosphate bond is stored and rapidly used to keep ATP levels up during short, intense activity. Creatine phosphate serves as a quick phosphate donor to ADP via the enzyme creatine kinase, reforming ATP so the muscle can continue contracting without delay. This makes the statement that best describes its role the one saying it donates a phosphate to ADP to form ATP.

Phosphocreatine is actually formed when ATP donates its phosphate to creatine, not from ATP and glucose together in a single step, and glucose isn’t directly involved in making phosphocreatine. It also doesn’t directly supply energy on its own; its purpose is to regenerate ATP quickly so energy can be used by the working muscles.