Aerobic energy system

• the aerobic system breaks down glucose, glycogen and fats to provide energy
• this takes place during coupled reactions
• the energy produced is used to resynthesise ADP into ATP

The aerobic system uses oxygen

It completely breaks down glucose

It produces H20 and CO2 

The system has three stages:

• Aerobic glycolysis
• Kreb's cycle
• Electron transport chain

• Glucose is broken down into pyruvic acid
• The presence of oxygen inhibits the accumulation of lactic acid
• Pyruvic acid combines with coenzyme A to form Acetyl CoA

• Takes place in cytoplasm
• Controlled by phosphofructokinase
• Produces the energy for the resynthesis of 2 ATP

• Acetyl CoA combines with oxaloacetic acid to form citric acid 
• Citric acid is further broken down

1). CO2 produced and removed via lungs

2). hydrogen atoms are removed (oxidation)

3). energy is produced to resynthesise two molecules of ATP

4). oxaloacetic acid is regenerated

• Takes place in matrix of mitochondria
• Produces byproduct of CO2

• Hydrogen atoms combine with coenzymes NAD and FAD 
• This forms NADH and FADH which are carried down electron transport chain
• Here hydrogen is split into H+ and e-
• ETC takes place in the cristae of mitochondria

1). hydrogen electron (e-) splits from hydrogen atom and travels down ETC

2). this provides energy to resynthesise 34 ATP

3). hydrogen ion (H+) combines with oxygen to form H2O (byproduct)

Total energy provided by aerobic energy system is 38 ATP

• 2 ATP from aerobic glycolysis
• 2 ATP from Kreb's cycle
• 34 ATP from Electron transport chain