A-Level PE AQA Energy Systems

The only usable form of energy in the body

A process in which glucose is converted to pyruvate to produce energy

The fluid that surrounds the nucleus of a muscle fibre and is the site where anaerobic respiration takes place

A series of cyclical chemical reactions that take place using oxygen in the matrix of the mitochondrion

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

An energy rich phosphate compound found in the sarcoplasm of the muscles

A reaction that occurs without the presence of oxygen

When energy required by one process is supplied by another process

Produces high powered energy for high intensity effort events

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

The amount of oxygen used to produce ATP

The maximum volume of oxygen that can be taken up by the muscles per minute

When there is not enough oxygen available at the start of exercise to provide all the energy (ATP) aerobically

The amount of oxygen consumed during recovery about that which would have been consumed at rest during the same time

The restoration of ATP and phosphocreatine stores and the re-saturation of myoglobin with oxygen

The point during exercise at which lactic acid quickly accumulates in the blood

The point when lactate levels go up above 4mmol/litre

A process which aids the removal of lactate and maintains acidity levels in the blood and muscle

The calculation of heat in physical changes and chemical reactions

Measures the production of CO2 and/or the consumption of O2

The ratio of carbon dioxide produced compared to oxygen consumed

Usually done at 2500m+ above sea level where the partial pressure of oxygen is low

ATP-ase to form ADP and Pi

Aerobic

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

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

More ATP made from one molecule of fatty acid than one molecule of glucose

2 ATP

2 ATP

34 ATP

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

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

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.