LEWIS: Anaerobic energy systems

Question 1

Energy system that the body uses to resynthesise ATP is dependent on the

Answer 1

intensity of work being carried out

Question 2

ATP breakdown and resynthesis is a

Answer 2

coupled reaction

Question 3

more intense the exercise = the more ATP used to provide energy for muscle fibre contraction, and therefore more ATP we need to

Answer 3

resynthesise

Question 4

2 anaerobic energy systems:

Answer 4

ATP-PC

Lactic acid

Question 5

(ATP-PC) phosphocreatine is an energy rich compound that when broken down releases energy to resynthesise

Answer 5

ATP

Question 6

ATP-PC equation:

Answer 6

PC-(creatine kinase)->P+C+ENERGY ) (exothermic)
V
ATP<-P+ADP+ENERGY (endothermic)

Question 7

(ATP-PC) For every molecule of PC that is broken down sufficient energy is released to resynthesise:

Answer 7

1 molecule of ATP

Question 8

(ATP-PC) Benefits of ATP-PC system:

Answer 8

• Energy released rapidly
• Rapid resynthesis of ATP (necessary for short bursts of maximal work)
• No waste products
• Rapid resynthesis of PC stores

Question 9

(ATP-PC) Disadvantages of ATP-PC system:

Answer 9

• Phosphocreatine stores are limited in muscle
• Only sufficient for 5-8s of high intensity/maximal work
• Take up to 3 min for PC stores to fully refuel
• Only 1 mole of ATP can be resynthesised through 1 mole of PC

Question 10

Lactate anaerobic energy system involves the partial breakdown (glycolysis) of

Answer 10

glucose

Question 11

(LACTATE/LACTIC ACID ENERGY SYSTEM) hydrogen ions are released during glycolysis, breakdown of glucose to pyruvate and complex chemical reactions occurring during the krebs cycle. These hydrogen ions are combined with oxygen in ETC to form water. This process works well for low-intensity exercise, but more ATP must be resynthesised as the level of work increases and therefore more glucose is broken down and more hydrogen is

Answer 11

transferred to the ETC

Question 12

(LACTATE/LACTIC ACID ENERGY SYSTEM) More oxygen becomes available as the ventilation rate and cardiac output increase. The amount of oxygen that can be made available to and used by muscle cells is finite, and is known as the

Answer 12

VO2 max

Question 13

(LACTATE/LACTIC ACID ENERGY SYSTEM) If body continues to work hard more hydrogen is released and at some point, so much hydrogen enters the ETC that it

Answer 13

exceeds the amount of oxygen available

Question 14

(LACTATE/LACTIC ACID ENERGY SYSTEM) Excess hydrogen ions cannot remain unattached and so combine with the pyruvate to form lactate. The point at which this occurs is known as the

Answer 14

lactate threshold

Question 15

(LACTATE/LACTIC ACID ENERGY SYSTEM) Benefits:

Answer 15

• ATP resynthesised quite quickly
• Presence of oxygen, lactic acid can be converted back into liver glycogen or used as a fuel through oxidation into CO2 and H2O
• Used to engage in maximal work

Question 16

(LACTATE/LACTIC ACID ENERGY SYSTEM) Drawbacks:

Answer 16

• Produces lactic acid as a fatigue by-product
• Higher fatigue
• Too much lactic acid = acidic pH = enzymes can’t work as well
• Muscle action = inhibited
• Oxygen debt