U3AoS2 - How does the Body produce energy? Flashcards
Name the Food Fuels
Carbohydrates
Fats
Proteins
Provide examples of Carbohydrates
Sugars
Starches
Bread
Pasta
Fruit
Vegetables
Jube lollies
White rice
Yield definition
Number of ATP resynthesised per molecule.
What is the yield of Carbohydrates?
36 ATP Molecules
Describe Fats
Preferred food source at rest and during prolonged submaximal exercise
Examples of fats
dairy products
oils
nuts
meat
butter
avocado
cheese
Yield and Oxygen cost of Fats.
Yield = 441
Oxygen cost (L/mole) = 5.5 (great oxygen cost)
Examples of protein
Meat, fish, eggs, legumes, and grains
Role and definition of Fuel/Substrates
Used to provide energy to resynthesise ATP from ADP + Pi.
Food fuel sources during rest:
- energy demand is low
- spare glycogen
- fats are main energy source
High and Low Gi Foods
Body doesn’t digest and absorb all carbohydrates at the same rate.
Glycaemic Index
Indicator of how quickly glucose is broken down and released into the blood stream over a 2-hour period of time.
ATP
Adenosine Triphosphate
ATP definition
- only energy source for muscular contractions
- splits when a phosphate group is removed
- Split releases energy required for muscular contractions to occur
Following the Breakdown of ATP
- For exercise to continue ATP needs to be resynthesised.
- Chemical energy provided by the breakdown of the bodies available fuel allows for this process to occur
ATP cycle
The constant process of ATP breakdown and resynthesis
What is the role of the energy systems in ATP resynthesis?
- All 3 energy systems and fuels contribute to the resynthesis of ATP at all times for muscle contraction and movement.
- Contribution will vary depending on the duration, intensity and availability of fuels.
Creatine Phosphate
- chemical fuel with a high energy phosphate bond for the rapid release if energy
- limited storage in the muscle
- only used by ATP-PC system
- Dominant fuel in maximal activities of durations less than 10 seconds.
Examples of activities that use PC
Long jump and weight lifting
Creatine Phosphate yield and capacity
- 10 seconds of PC stored in the muscle
- very low yield and capacity
- single bond splits very rapidly and can rebuild ATP at the most rapid rate
Glycogen
Used via aerobic and anaerobic glycolysis systems.
- more complex fuel and rebuilds ATP at a slower rate than PC.
- 90 minutes stored in the muscles and liver
Anaerobic glycolysis
Incomplete breakdown of glycogen aerobically (without oxygen)
Yield = 2 at a rapid rate
Aerobic glycolysis
Complete breakdown of glycogen aerobically.
Yield = 36 at a slower rate
Triglycerides
- aerobic system
- much more complex fuel (many bonds)
- ATP is rebuilt at a very slow rate
- high yield
- Dominant at low intensities, periods of passive recovery and when glycogen is depleted.
As athletes move from rest to submaximal intensity
- fats will decrease their contribution
- CHO will increase their contribution enabling ATP to be used at a faster rate as less oxygen required.
The effect of aerobic training on fats and carbohydrate usage
Increased ability to oxidise fats, shifts crossover to the right.
Process called glycogen sparing by using fats as preferred fuel source.
The ATP-PC System
- least complicated energy system
- Rebuild ATP at the most rapid rate without oxygen due to simple chemical pathway
- Lowest yield
- Produces energy by breaking down CP
- Finite, limited to the amount of energy stored.
Advantages of the ATP-CP system
- rebuilds ATP at the most rapid rate (very simple chemical pathway)
- enables athletes to work at maximal intensities (95%+ HRM)
How does the ATP-PC system resynthesise ATP?
- uses chemical fuel CP, a simple fuel with only one bond.
- PC splits and releases the energy to rebuild the ATP molecule at a very rapid rate.
By-Products of the ATP-PC system
Creatine + Pi
Disadvantages of the ATP-PC system
- has a very low capacity (yield 1 ATP molecule)
- Fuel CP depletes in 10 seconds of maximal intensity work.
ATP - PC Capacity
Finite, fuel CP depletes in 10 seconds of maximal intensity.
ATP- PC sporting examples
- long jump
- weight lifting
- tackle
ATP Capacity
Depletes after 2 seconds
Recovery required for the ATP-PC system
- passive recovery is the most effective strategy
- restores PC at the most rapid rate using on 35% HRM
- Low intense exercise such as walking/standing
- enables the athlete to recover faster
Muscular Hypertrophy
- anaerobic training results in greater PC stored in the muscle as skeletal muscles get bigger
- results in a greater capacity of ATP-PC system
- maintain maximal intensities for a longer period of time
- decrease contribution of anaerobic system
ATP - PC Fatigue mechanism
CP depletion
Rates of PC replenishment
30 seconds = 70%
60 seconds = 87%
3 minutes = 98%