ATP-PC system

Question 1

Information (5 points)

Answer 1

• Called upon during high intensity/ short duration exercise that lasts for around 10 secs.
• Anaerobic system.
• Fuel= Phosphocreatine.
• PCr= stored in the muscle alongside ATP for rapid access.
• Takes place in the sarcoplasm.

Question 2

ATP-PC system process

Answer 2

1. Increase of ADP and Pi in the muscle cells= release of creatine kinase.
2. PCr= broken down by creatine kinase into creatine and phosphate.
3. Energy is released (exothermic reaction).
4. Energy is not used for muscular contraction but to resynthesise ATP in the muscle.
5. Energy reconnects ADP + Pi making ATP (endothermic reaction).
6. ATP= broken down once again to produce energy for muscular contraction.

Question 3

Coupled reaction

Answer 3

• ATP breakdown and ATP resynthesis happen simultaneously.
• ATP is automatically regenerated through PCr breakdown.

Question 4

Advantages

Answer 4

1. ATP resynthesised rapidly.
2. PCr stores recovered quickly:
   
   • 50%= 30 secs
   • 100%= 3 mins
3. No fatiguing by-products produced (lactic acid).
4. Time ATP-PC works can be extended through creatine supplements.

Question 5

Disadvantages

Answer 5

1. Limited supply/ lasts 10 seconds.
2. PCr replenishment can only occur during rest conditions.
3. Only 1 mole of ATP can be resynthesised through 1 mole of PCr.