Question

Since fast twitch muscle fibers are recruited during performance of anaerobic-type activities, and slow-twitch muscle fibers are recruited during performance of aerobic-type activities, then which fiber type is expected to contain more phosphocreatine?

Answer 1

Phosphocreatine

Step-by-step explanation:

• The phosphate is transferred from ATP to creatine to make creatine phosphate. As creatine phosphate, or phosphocreatine, is more stable than ATP, it provides an effective way to store energy. During contraction, the contractile protein myosin breaks down ATP producing ADP and phosphate. The energy stored in creatine phosphate is then used to recharge the ADP as follows: CP + ADP -> Creatine + ATP
• The phosphate is now transferred back to ADP to make ATP, and the ATP can be used for contraction. These reactions are catalyzed by the enzyme we call creatine phosphokinase (or CPK), and it's located in the muscle cell. For example, this happens with a myocardial infarction, or a heart attack, that results in heart muscle damage
• Phosphocreatine or creatine phosphate - is the phosphorylated type of creatine. It is basically found endogenously in the skeletal muscles of vertebrates where it serves a basic job as a quickly acting vitality support for muscle cell activities like compressions by means of its capacity to recover adenosine triphosphate (ATP) from adenosine diphosphate (ADP)
• Hence, the right answer is "type II fiber expected to contain more phosphocreatine"