aerobic energy system

Question 1

where does energy come from

Answer 1

adenosine triphosphate ATP which is the only useable form of chemical energy in the body

Question 2

how does energy from ATP get released

Answer 2

1. energy stored in ATP is released by breaking down bonds that hold compound together
2. ATPase (enzyme) used to break down ATP leaving adenosine di-phosphate (ADP)
3. body has to constantly rebuild ATP by converting the ADP and pi back to ATP
4. we re-synthesise ATP from 3 different chemical reactions fuelled by either food or PC (found in muscles)
5. conversions of fuels to energy takes place in one to the 3 energy systems

Question 3

3 energy systems

Answer 3

1. aerobic system
2. ATP-PC system
3. anaerobic glycolytic system

Question 4

beta oxidation

Answer 4

• stored fat is broken down into glycerol and free fatty acids for transportation by the blood
• fatty acids converted into acetyl coenzyme A -> krebs cycles
• more ATP can be made from 1 molecule of fatty acid then glucose therefore fatty acid will be predominant energy source but depends on fitness of performer

Question 5

advantages of aerobic system

Answer 5

• 36 ATP produced
• no fatiguing by-products
• lots of glycogen and triglyceride stores so exercise can last for a long time

Question 6

disadvantage of aerobic system

Answer 6

• takes a while for enough oxygen to become available

- fatty acid transportation to muscles is low and requires 15% more oxygen to be broken down than glycogen

Question 7

explain stages of aerobic system

Answer 7

glycolysis

1. breakdown of glucose to pyruvic acid in sarcoplasm of the muscle cell
2. 2 molecules of ATP is formed for every molecule of glucose
3. pyruvic acid is oxidised into 2 acetyl groups and carried to krebs cycle by coenzyme A

krebs cycle

1. 2 acetyl groups diffuse into the matrix of mitochondria
2. combine with oxaloacetic acid forming citric acid
3. oxidative carboxylation - carbon and hydrogen given off. Carbon -> C02 and breathed out
4. hydrogen is taken to the electron transport chain
5. results in the production of 2 ATP molecules

electron transport chain

• hydrogen splits into hydrogen ions and electrons are charged with potential energy
• hydrogen ion are oxidised to form water
• hydrogen electrons provide energy to re-synthesise ATP
• 34 ATP formed

Question 8

when is the aerobic system mostly used

Answer 8

• low intensity exercise
• high oxygen supply
• jogging

Question 9

how many phosphate molecules are there in ATP and ADP

Answer 9

ATP = 3 molecules of phoshphate
ADP = 2 molecules of phosphate