Energy systems Flashcards
(45 cards)
What is ATP?
Adenosine Triphosphate
It is the only useable form of energy in the body.
It is one molecule of adenosine and three of phosphate.
It has high energy bonds that, when broken down, release the energy.
How is ATP broken down?
Energy is released by breaking the bonds that hold the compound together.
ATPase is used to break it down.
It leaves adenosine diphosphate (ADP) and an inorganic phosphate (Pi).
ATP + ATPase = ADP + Pi + energy.
Exothermic reaction.
What is glycolysis?
The first stage of the aerobic system.
It is anaerobic.
It takes place in the sarcoplasm.
It produces two molecules of ATP for each glucose molecule.
What are the stages of the aerobic system?
Glycolysis
Krebs cycle
Electron transport chain
What are the three energy systems?
Aerobic
ATP-PC
Anaerobic glycolytic
What is sarcoplasm?
The fluid that surrounds the nucleus of muscle fibre.
It is the site where anaerobic respiration takes place.
When is the aerobic system used?
For activity lasting over 3 minutes.
When exercise intensity is low and oxygen supply is high.
What happens during aerobic glycolysis?
The glycogen is broken down into glucose by glycogen phosphorylase.
The glucose is broken down into pyruvic acid by phosphofructokinase (PFK).
Coenzyme A is added and the pyruvic acid splits into two acetyl groups called acetyl coenzyme A.
What is the Krebs cycle?
The second stage of the aerobic system.
It takes place in the matrix of the mitochondria.
It is a series of cyclical chemical reactions that take place using oxygen.
2 molecules of ATP are produced.
What happens in the Krebs cycle?
The acetyl coenzyme A diffuses into the matrix.
It combines with oxaloacetic acid, and forms citric acid.
Hydrogen is removed from the citric acid, and the rearranged form undergoes oxidative carboxylation - carbon and hydrogen are given off.
The carbon forms carbon dioxide and is breathed out.
The hydrogen is taken to the electron transport chain.
What is beta oxidation?
Fats can also enter the Krebs cycle.
Stored fat is broken down into glycerol and free fatty acids for transportation by the blood.
(Triglycerides are broken down by lipase).
They are then converted into acetyl coenzyme A, which enters the Krebs cycle.
From this point, fat metabolism follows the same pathway as glycogen metabolism.
Why are fats used instead of glycogen?
More ATP can be produced from one molecule of fatty acids than one of glucose.
So in long-duration, low-intensity exercise, fatty acids will be the predominant energy source.
This does depend on the fitness of the performer.
What is the electron transport train?
The third stage of the aerobic system.
A series of chemical reactions that take place in the cristae of the mitochondria.
Hydrogen is oxidised to form water.
34 ATP molecules are produced.
What happens in the electron transport chain?
Hydrogen is carried to the electron transport chain by electron carriers.
The hydrogen splits into hydrogen ions and electrons and they are charged with potential energy.
The hydrogen ions are oxidised to form water.
The hydrogen electrons provide the energy to re-synthesise ATP.
What are the advantages of the aerobic system?
High energy yield and very efficient - 1:38 ATP.
No fatiguing by-products.
Long duration system.
What are the disadvantages of the aerobic system?
Only used for moderate intensity.
No explosive movements used.
There is a delay in oxygen delivery.
What is the ATP-PC system?
It uses phosphocreatine (PC) as its fuel.
It can be broken down quickly and easily to release energy to re-synthesise ATP.
It is an anaerobic process.
What is phosphocreatine?
It is an energy-rich phosphate compound.
Found in the sarcoplasm of the muscles.
How does the ATP-PC system provide energy?
It resynthesises ATP when the enzyme kinase detects high levels of ADP.
Phosphocreatine = Phosphate + creatine + energy
This energy is then used to convert ADP to ATP in a coupled reaction.
Energy + Pi + ADP = ATP
Endothermic reaction.
What are the advantages of the ATP-PC system?
It doesn’t produce (fatiguing) by-products.
It delays the onset of the anaerobic glycolytic system.
PC is in the muscle so is readily available.
ATP can be regenerated quickly and doesn’t require oxygen.
What are the disadvantages of the ATP-PC system?
PC only lasts 5-8 seconds, and is only replenished after 3 minutes in low intensity exercise where oxygen is available.
For every molecule of PC broken down, only enough energy is produced to create one ATP.
So it is quite inefficient.
Only provides energy for high intensity exercise for a short time, <10 seconds.
Limited PC stores in the body.
What are sporting examples of when ATP-PC system is used?
Shotput, discus, javelin throw.
Tennis forehand.
Long jump, triple jump, high jump.
Free kick in football.
Golf.
100m sprint.
Power lifting.
What is the process of the anaerobic glycolytic system?
Low levels of PC activate the enzyme glycogen phosphorylase.
This enzyme breaks down glycogen into glucose.
The enzyme phosphofructokinase breaks glucose down into pyruvic acid.
The enzyme lactate dehydrogenase breaks down pyruvic acid into lactic acid.
What is the anaerobic glycolytic system?
Energy is released to allow ATP re-synthesis.
2 ATP molecules are produced for one molecule of glucose.
It takes place in the sarcoplasm of the muscle cell where oxygen is not available.
The system can last 2-3 minutes, if not working at the highest intensity.
