ATP-PC system

Question 1

what does the ATP-PC system use as its fuel

Answer 1

phosphocreatine PC

Question 2

phosphocreatine

Answer 2

an energy rich phosphate compound found in the sarcoplasm of the muscles and can be broken down quickly and easily to release energy to re-synthesise ATP

Question 3

when is the ATP-PC system used

Answer 3

• short duration
• highly explosive
• long jump take-off
• shot putt

Question 4

how does ATP-PC system provide energy

Answer 4

Anaerobic process
- when the enzyme creatine kinase detects high levels of ADP, it re-synthesises ATP

It breaks down the Phosphocreatine in the muscles to phosphate and creatine, releasing energy

energy is then used to convert ADP to ATP in a coupled reaction

PC -> Pi + C + energy energy -> Pi + ADP -> ATP

• for every molecule of PC broken down there is enough energy released to create one molecule of ATP.

Question 5

advantage of ATP-PC system

Answer 5

• no fatiging by-products
• ATP resynthesises rapidly
• PC stores replenished quickly
• possible to extend ATP-PC system through creatine supplementation

Question 6

disadvantage of ATP-PC system

Answer 6

• stores are limited as there is only enough PC to last for 5-8 secs
• can only be replenished during low intensity work when oxygen is available
• only 1 molecule of ATP can be re-syntehsised for every molecule of PC so inefficient

Question 7

which enzyme catalyses the conversion of ATP to ADP to release energy

Answer 7

ATPase

Question 8

what is the difference in ATP generation between slow and fast twitch muscle fibres

Answer 8

fast twitch has a lower capacity for ATP but can generate ATP more quickly

slow twitch has a higher capacity for ATP but generate ATP more slowly