Energy Sysfems Flashcards
the aerobic system
- exercise intensity is low
- oxygen supply is high
- breaks down glucose into carbon dioxide and water which in the presence of oxygen is more efficient
- complete oxidation of glucose can produce up to 38 molecules of ATP
- fats in form of fatty acids can also be broken down
- products of fat and protein metabolism are reduced to molecule acetyl coenzyme A that enters the Krebs cycle
what are the 3 stages for the aerobic system
1 glycolysis
- anaerobic, takes place in sarcoplasm of the muscle cell
- breaks down glucose to pyruvate
- every molecule of glucose k glycolysis = 2 molecules of ATP is formed
2 krebs cycle
- 2 acetyl groups diffuse into matrix of the mitochondria
- acetyl groups combine with oxaloacetic acid, forming citric acid
- hydrogen removed from citric acid and then undergoes oxidative carboxylation - carbon and hydrogen are given off
- carbon forms carbon dioxide which is transported to lungs & breathed out and hydrogen is taken to electron transport chain.
- 2 molecules of ATP
3 electron transport chain
- hydrogen carried to ETC by hydrogen carriers
- occurs in mitochondria & hydrogen splits into hydrogen ions & electrons& they are charged with potential energy
- hydrogen ions are oxidised to form water while the hydrogen electrons provide the energy to re synthesise ATP
- 34 ATP are formed
what is beta oxidation
breakdown of saturated fatty acids to aid in energy production and are converted into acetyl coenzyme A- entry molecule for krebs cycle
advantages and disadvantages of the aerobic system
advantages:
- more ATP produced - 38
- no fatiguing by products (co2 and water)
- lots of glycogen and triglyceride stores so exercise can last
disadvantages:
- takes a while for enough oxygen to become available to meet demands of activity & ensure glycogen and fatty acids are completely broken down
- fatty acid transportation to muscles is low and also requires 15% more oxygen to be broken down than glycogen
ATP- PC system
- phosphocreatine PC fuel
- found in sarcoplasm
- can be broken down quickly to release energy to re synthesise atp
- long jump, shot put
- only enough PC to last 5-8 secs
- only replenished in low intensity work
how does the ATP PC system work
- anaerobic
- re synthesises ATP when enzyme creatine kinase detects high levels of ADP
- breaks down phosphocreatine in muscles to phosphate and creatine, releasing energy
- energy used to convert ADP to ATP
- for every molecule of PC broken down , 1 molecule of ATP
Advantages and disadvantages of ATP- PC system
- ATP can be resynthesised rapidly
- PC stores resynthesised quickly- 30s = 50% replenishment and 3 mins = 100%
- no fatiguing by products
disadvantages: - only limited supply of PC in muscle cell
- only one molecule of ATP can be re synthesised for every molecule of PC
- PC re synthesis can only take 0ace in the presence of oxygen
what is the anaerobic glycolytic system
provides energy for high intensity activity longer than ATP PC system
- how long system lasts depends on fitness of individual & how high exercise intensity is
how does the anaerobic glycolic system work to provide energy
glycogen broken down to glucose
further broken down into pyruvate by PFK enzyme
takes place in sarcoplasm where oxygen not available
pyruvic acid further broken down into lactic acid by LDH enzyme
during anaerobic glycolysis, energy is released to allow ATP are synthesis
- 2 molecules of ATP produced for one molecule of glucose broken down
advantages and disadvantages of anaerobic glycolytic system
advantages:
- ATP can be resynthesised quite quick due to few chemical reactions and lasts longer than ATP PC system
- presence of oxygen, lactic acid converted back to liver glycogen or used as a fuel through oxidation into carbon dioxide and water
- used for sprint finsih
disadvantages:
- lactic acid as by product- accumulation in the body de natures enzymes and prevents them increasing the rate at which chemical reactions take place
- only small amount of energy can be released from glycogen under anaerobic conditions
what is energy continuum
type of respiration used by physical activities. whether it is aerobic or anaerobic respiration depends on the intensity and duration of the exercise
- highly explosive, short duration= ATP-PC system
- long duration, lower intensity= aerobic system
- game where intensity is constantly changing = mix of all three energy system
ATP generation in slow twitch fibres
slow twitch= low to medium intensity = aerobic
- produces maximum amount of atp available from each glucose molecule (up to 36 atp)
- production is slow but these fibres are more endurance based so less likely to fatigue
ATP generation in fast twitch muscle fibres
high intensity = anaerobic
- anaerobic much quicker than aerobic
- atp production in the absence of oxygen is not efficient - only 2 ATP produced per glucose molecule
- production of atp fast but can’t last for long as fibres have least resistance to muscle fatigue
energy transfer during long duration/ lower intensity exercise
- aerobic system
- low intensity exercise, demand for oxygen can easily be met and glucose can be broken down much more efficiently when oxygen is present
- fats used for as intensity increases, uses become limited because more oxygen than glucose is required
what is sub maximal oxygen deficit
not enough oxygen available at the start of exercise to provide all the energy (ATP) aerobically
