Energy Systems Flashcards
What is ATP?
The only usable form of energy in the body
What is glycolysis?
A process in which glucose is converted to pyruvate to produce energy
What is the sarcoplasm?
The fluid that surrounds the nucleus of a muscle fibre and is the site where anaerobic respiration takes place
What is the krebs cycle?
A series of cyclical chemical reactions that take place using oxygen in the matrix of the mitochondrion
What is the electron transport chain?
It is involved in a series of chemical reactions in the cristae of the mitochondria where hydrogen is oxidised to water and 34 ATP are produced
What is phosphocreatine?
An energy rich phosphate compound found in the sarcoplasm of the muscles
What does it mean to be anaerobic?
A reaction that occurs without the presence of oxygen
What is a coupled reaction?
When energy required by one process is supplied by another process
What is the short term lactate anaerobic system?
Produces high powered energy for high intensity effort events
What is the energy continuum?
A term which describes the type of respiration used by physical activities. Whether it is aerobics or anaerobic respiration depends on the intensity and duration of the exercise
What is oxygen consumption?
The amount of oxygen used to produce ATP
What is VO2 max?
The maximum volume of oxygen that can be taken up by the muscles per minute
What is sub-maximal oxygen deficit?
When there is not enough oxygen available at the start of exercise to provide all the energy (ATP) aerobically
What is EPOC?
The amount of oxygen consumed during recovery about that which would have been consumed at rest during the same time
What is the fast component?
The restoration of ATP and phosphocreatine stores and the re-saturation of myoglobin with oxygen
What is the lactate threshold?
The point during exercise at which lactic acid quickly accumulates in the blood
What is OBLA (Onset of Blood Lactate Accumulation)?
The point when lactate levels go up above 4mmol/litre
What is buffering?
A process which aids the removal of lactate and maintains acidity levels in the blood and muscle
What is calorimetry?
The calculation of heat in physical changes and chemical reactions
What is indirect calorimetry?
Measures the production of CO2 and/or the consumption of O2
What is the respiratory exchange ratio (RER)?
The ratio of carbon dioxide produced compared to oxygen consumed
What is altitude training?
Usually done at 2500m+ above sea level where the partial pressure of oxygen is low
Which enzyme breaks down ATP?
ATP-ase to form ADP and Pi
Which is the preferred energy system when exercise intensity is low and oxygen supply is high?
Aerobic
Describe the three stages of the aerobic system as it works to provide energy?
1) Glycolysis - this stage is anaerobic and takes place in the sarcoplasm of the muscle cell. Glucose is broken down into pyruvic acid. For every molecule of glucose undergoing glycolysis, a net of two molecules of ATP is formed. Pyruvic acid is split into two acetyl groups and is carried into the krebs cycle by coenzyme A.
2) Krebs Cycle - Acetyl coenzyme A diffuses into the matrix of the mitochondria and a series of cyclical chemical reactions occur. Acetyl coenzyme A combines with oxaloacetic acid forming citric acid. Hydrogen is removed from the citric acid and the rearranged form of citric acid undergoes ‘oxidative carboxylation’ which means carbon and hydrogen are given off. Carbon forms CO2 which is transported to the lungs and breathed out. Hydrogen is taken to the electron transport chain. Two molecules of ATP are produced
3) Electron Transport Chain - hydrogen carried to ETC by hydrogen carriers. This occurs in the cristae of the mitochondria. Hydrogen splits into hydrogen ions and electrons are charged with potential energy. The ions are oxidised to form water, while the electrons provide energy to re-synthesise ATP. 34 molecules of ATP are formed
How do fats enter the krebs cycle?
Stored fat is broken down into glycerol and free fatty acids for transportation by the blood. These fatty acids undergo a process called beta-oxidation whereby they are converted into acetyl coenzyme A, which is the entry molecule for the krebs cycle. Fat metabolism follows the same path as glycogen metabolism from this point. More ATP can be made from one molecule of fatty acids than one molecule of glucose, which is why fatty acids are the predominant energy source for long-duration, low-intensity exercise
Why are fatty acids the predominant energy source for long duration, low-intensity exercise?
More ATP made from one molecule of fatty acid than one molecule of glucose
How many molecules of ATP produced in glycolysis?
2 ATP
How many molecules of ATP produced in the krebs cycle?
2 ATP
How many molecules of ATP produced in the ETC?
34 ATP
Why is phosphocreatine used?
It can be broken down quickly and easily to release energy to re-synthesise ATP. Its rapid availability is important for single maximal movement such as long jump take off or shot put
How does the ATP-PC system work to provide energy?
It is an anaerobic process and re-synthesis ATP when the enzyme creatine kinase detects high levels of ADP. It breaks down phosphocreatine in the muscles to phosphate and creatine, releasing energy.
PC > Pi + ADP > ATP
The energy is then used to convert ADP to ATP in a coupled reaction. Energy > Pi + ADP > ATP
What is the short term lactate anaerobic system/anaerobic glycolytic system and why is it used?
An energy system that provides energy for high-intensity activities for longer than the ATP-PC system. However, how long this system lasts depends on the fitness of the individual and the intensity of the exercise. Working at a maximum intensity will cause the system to last a shorter time because the demand for energy is extremely high. ex - an elite 400m runner will not be able to run it immediately after at the same pace even though it only lasted 45 secs. If the intensity is reduced the system can last 2-3 minutes because the demand for energy is slightly lower.
