Energy Systems Flashcards
where does the energy we use for muscle contractions come from
adenosine triphosphate (ATP). the energy that is stored in ATP is released by breaking down the bonds that hold this compound together. enzymes are uysed to break down the bonds.
what enzyme breaks down ATP into ADP + Pi
ATPase
The conversion of fuel into energy takes place in one of three pathways which are
- aerobic system
- the ATP-PC system
- the anaerobic glycolytic system
When is the aerobic system the preferred pathway
When the exercise intensity is low and oxygen availability is high
What are the by-products of the aerobic system
- Carbon Dioxide
- water
The complete oxidation of glucose can produce how many ATPs (aerobic systems)
38 ATPs
The aerobic system has 3 stages which are
- Glycolysis
- Kreb’s Cycle
- Electron Transport Chain
What is glycolysis
- the breakdown of glucose into pyruvate
- takes place in the sarcoplasm
- for every molecule of glucose undergoing glycolysis, a net of two molecules of ATP is formed.
What happens to the pyruvate so it can move to the next stage of the system
The pyruvic acid is oxidised into two acetyl groups and is then carried into Kreb’s cycle by coenzyme A
Where does the coenzyme a come from (aerobic system)
The products of the metabolism of fats and proteins are reduced to the molecule acetyl coenzyme a.
what is the kreb’s cycle
the two acetyl groups (formerly pyruvic acid) diffuse into the matrix of the mitochondria. and they undergo a complex cycle of reactions
describe what happens in the kreb’s cycle
- the two acetyl groups combine with oxaloacetic acid to from citric acid.
- hydrogen is removed from the citric acid and the now rearranged form of citric acid undergoes oxidative carboxylation (simply meaning carbon and hydrogen are given off)
- the carbon forms carbon dioxide which is transported to the lungs and breathed out
- the hydrogen is transported to the electron transport chain
- the result of these reactions result in the production of 2 ATP molecules
what is the electron transport chain
- the hydrogen from the krebs cycle is carried to the electron transport chain by hydrogen carriers
- occurs in the cristae of the mitochondria
- the hydrogen splits into hydrogen and electrons and they are charged with potential energy
- the hydrogen ions are oxidised to from water while the hydrogen electrons provide the energy to re-synthesise ATP
- throughout this process 34 ATP are formed
other than glucose what other fuels can the aerobic system use
- fats in the form of fatty acids and proteins in the from of amino acids
what is beta oxidation
- when stored fat is broken down into glycerol and free fatty acids
- the fatty acids then undergo a process called beta oxidation where it is converted to coenzyme a (the entry molecule for the krebs cycle)