Aerobic system

Question 1

The aerobic system

Answer 1

> Takes over from the glycolytic system after 3 minutes due to lactic acid build up
Lasts for several hours
Fuel source: carbohydrates, fats, proteins
Requires O2
Endurance events
Recovers in 1-3 days
Fatigue once carbohydrate stores are exhausted
36ATP
No harmful by-products

Question 2

3 Stages of the aerobic system

Answer 2

1) Aerobic glycolysis
2) Krebs cycle
3) Electron transport chain

Question 3

1) Aerobic glycolysis

Answer 3

1) Stored glycogen is converted to glucose
2) Glucose is broken down into 2 pyruvic acid
3) 2ATP are synthesised
4) O2 is present, allowing the reaction to proceed
5) 2 pyruvic acid diffuses into the matrix of mitochondria

Question 4

2) Krebs cycle

Answer 4

1) 2 moles of pyruvic acid combine with acetyl CoA to form citric acid
2) Citric acid is oxidised and hydrogen is removed, to be used in the next stage
3) Carbon and oxygen are left behind (forms CO2), which is exhaled
4) 2ATP is synthesised
5) Free fatty acids (facilitated by lipase), and amino acids act as a fuel

Question 5

3) Electron transport chain

Answer 5

1) Hydrogen (from Krebs) is carried to ETC by NADs and FADs (carriers)
2) They go through a series of chemical reactions and split into H+ and e-
3) During a reaction, H+ are oxidised to form H2O, and e- provide energy to resynthesise ATP
4) Energy is released to form 32 moles of ATP (from each glucose molecule)

Question 6

Total energy yield

Answer 6

1) Aerobic glycolysis = 2ATP
2) Krebs cycle = 2ATP
3) Electron transport chain = 32ATP

= 36ATP

By-products: CO2+H2O (easily expelled)

Question 7

Equation

Answer 7

Glucose+36ADP+36P+6O2 ->
36ATP+6H2O

Question 8

Aerobic system: Sporting examples

Answer 8

> Endurance events
Marathon, triathlon, Tour de France

Question 9

Training the aerobic system

Answer 9

> Continuous training - constant intensity (>20min)
Fartlek training - varying speed/intensity of training for prolonged period
Interval training - work:rest ratio

Question 10

Aerobic system: +

Answer 10

> Large fuel stores
Long duration
Very high energy yield (36ATP)
No fatiguing by-product

Question 11

Aerobic system: -

Answer 11

> Only used for moderate/low intensity
Delay for O2 delivery
Slow energy production
Lengthy recovery (1-3 days)