ATP-PC system

Question 1

What is the ATP-PC system

Answer 1

An anaerobic system (no oxygen)

Question 2

When is the ATP-PC system called upon?

Answer 2

During high intensity/short duration exercise, that lasts around 10 seconds

Question 3

Give an example of an activity that uses the ATP-PC system

Answer 3

100m sprint

Question 4

What is the fuel used to power ATP resynthesis?

Answer 4

Phosphocreatine

Question 5

Why is phosphocreatine stored in the muscle cells?

Answer 5

Stored alongside ATP for rapid access!!! (Mobile phone)

Question 6

Where does the ATP-PC system take place?

Answer 6

In the sarcoplasm

Question 7

What happens following ATP being broken down?

Answer 7

1. Increase of ADP & Pi in muscle cell, this stimulates release of creatine kinase
2. PCr broken down by creatine kinase into creatine and phosphate
3. Energy released (exothermic reaction!!)
4. Energy used to resynthesise ATP
5. Energy reconnects ADP & Pi to make ATP, through endothermic reaction
6. ATP broken down once again to produce energy for muscular contraction

Question 8

What is the coupled reaction?

Answer 8

Both ATP breakdown and ATP resynthesis happen simultaneously in the muscle cell
- As soon as ATP is broken down it is automatically regenerated through PCr breakdown

Question 9

Give 3 advantages of the ATP-PC system

Answer 9

• ATP resynthesised rapidly
• PCr stores are recovered very quickly
  50% is recovered in 30 seconds
• No fatiguing by-products that can slow down the recovery process

Question 10

Why is the quick recovery of PCr stores an advantage?

Answer 10

50% of PCr stores are recovered in 30 seconds , meaning a performer can recover and repeat the same action

Question 11

Give 3 disadvantages of the ATP-PC system

Answer 11

• Limited supply (works for only 10 secs)
• PCr replenishment only takes place in presence of oxygen
• Only one mole of ATP can be re-synthesised through one mole of PCr