Energy Systems Flashcards
What does ATP stand for?
Adenosine triphosphate
What is ATP composed of?
1 molecule of adenosine and 3 phosphates
What are the names of the three energy systems?
The aerobic system
The ATP-PC system
The anaerobic glycolytic
What are the three stages of the aerobic energy system?
Glycolysis
Krebs cycle
Electron transport chain
Describe the process of glycolysis.
Glycolysis occurs in the sarcoplasm of muscle cell and is the breakdown of glucose into pyruvic acid. For every 1 molecule of glucose broken down 2 molecules of ATP are formed.
Describe what happens after glycolysis to pyruvic acid before it can enter the Krebs cycle.
The pyruvic acid is oxidised into two acetyl groups and is carried into the Krebs cycle by coenzyme A.
Describe the process of the Krebs cycle.
The two acetyl groups diffuse into the matrix of the mitochondria. Here the acetyl groups combine with oxaloacetic acid to form citric acid. Then hydrogen is removed from the citric acid and the acid undergoes oxidative carboxylation (carbon and oxygen are given off). The carbon dioxide given of forms carbon dioxide which is transported to the lungs and breathed out. The hydrogen given off is taken to the electron transport chain. This cycle produces 2 molecules of ATP.
Describe the process of the electron transport chain.
Hydrogen is carried into the hydrogen transport chain by hydrogen carriers. this process occurs in the cristae of the mitochondria. During this process, the hydrogen splits into hydrogen ions and electrons. The hydrogen ions are oxidised to form water, the hydrogen electrons provide the energy to resynthesise ATP. This process produces 34 ATP molecules.
What is beta-oxidation?
Beta-oxidation occurs after stored fat is broken down into glycerol and fatty acids. After this happens beta-oxidation occurs, the fatty acids are converted into acetyl coenzyme A which then enters the Krebs cycle.
What are the advantages of the aerobic system?
36 ATP molecules are produced
No fatiguing by-products are produced
Lots of glycogen and fats stores in the body so exercise can last a long time
What are the disadvantages of the aerobic system?
It takes a while for enough oxygen to become available
The transportation of fatty acid to muscles is low and requires 15% more oxygen to be broken down than glycogen
What kind of exercise is the aerobic system used in?
Low intensity, long duration, aerobic exercise such as marathon running.
What is the ATP-PC system?
This energy system uses phosphocreatine as the fuel. It is an anaerobic process and re-synthesises ATP when creatine kinase detects high levels of ADP. When high levels of ADP are detected phosphocreatine is broken down into phosphate, creatine and energy. the phosphate and energy given off by this reaction are used to re-synthesised ATP. For every molecule of phosphocreatine broken down 1 molecule of ATP is formed.
What are the advantages of the ATP-PC system?
ATP is rapidly re-synthesised
Phosphocreatine stores can be re-synthesised quickly
There are no fatiguing by-products
The duration of the system can be increased through the use of creatine supplements
What are the disadvantages of the ATP-PC system?
There is a limited supply of phosphocreatine
Only 1 ATP molecule is re-synthesised per phosphocreatine molecule
The re-synthesise of the phosphocreatine stores can only occur in the presence of oxygen
What kind of exercise is the ATP-PC system used in?
High intensity, short-duration exercise. This system produces enough energy for 5-8 seconds so this energy system is good for events like 100m sprints.
What is the anaerobic glycolytic system?
When phosphocreatine systems are low the enzyme glycogen phosphorylase is activated to break down the glycogen into glucose which is then further broken down into pyruvic acid. This process takes place in the sarcoplasm of muscle cells when oxygen is not available. Because this is an anaerobic process the pyruvic acid is further broken down into lactic acid.
What are the advantages of the anaerobic glycolytic system?
ATP can be re-synthesised quickly
What are the disadvantages of the anaerobic glycolytic system?
Lactic acid is a by-product produced which denatures enzymes.
Only a small amount of energy is released.