Which one of the following statements concerning creatine ph

Which one of the following statements concerning creatine phosphate and creatine phosphokinase in muscle is correct?

            a.         A reserve of creatine phosphate is established during contraction when metabolic pathways are more easily able to maintain a constant ATP level.

            b.         Creatine phosphate serves as the last reserve of energy to sustain long term exercise.

            c.         The endogenous creatine biosynthesis pathway can not generate enough creatine to replace that lost to formation of creatinine.

            d.         A lower than normal level of creatine phosphokinase in the blood is diagnostic of muscle cell damage.

            e.         During contraction creatine phosphokinase located on the myofibrils will convert ADP and creatine phosphate to ATP and creatine.

Solution

Answer: (e)

During contraction creatine phosphokinase located on the myofibrils will convert ADP and creatine phosphate to ATP and creatine.

When contraction begins and the ADP level starts to rise, creatine kinase catalyzes the transfer of a high-energy phosphate from creatine phosphate back to ADP. This direct phosphorylation quickly generates new ATP molecules.