The Three Energy Systems Working together to Produce ATP Flashcards
The role of ATP (how energy is produced, what it creates and how it returns to ATP)
Every muscular contraction is due to ATP (adenosine triphosphate being split apart and releasing energy.
After being split, it creates ADP and inorganic phosphate (Pi) which must resynthesise back to ATP in order to continue to exercise.
ATP resynthesis occurs through the 3 energy systems working together (interplay) to provide the energy that is required.
Chemical Fuels (ATP [what is it? how much is stored?])
The major source for muscular contraction (no ATP= no muscular contraction)
One ATP molecule consists of one adenosine molecule with three phosphates joined together in a row
The human body only has a small amount stored in the muscles for quick access (roughly enough for 2-3seconds of work)
PC (phosphate creatine)
Broken down to resynthesise ATP as a part of the ATP-PC energy system.
Food Fuels (carbohydrates)
CHO(carbon, hydrogen, oxygen)
-Sugars & starches such as fruit, cereal, bread, pasta, rice, nuts and vegetables
55-60% recommended daily intake.
They are the preferred source of energy during exercise as they require less oxygen to break down. CHOs provide glucose which is then converted to glycogen and stored in the muscles and liver.
They provide a greater yield than the ATP-PC system but at a slower rate.
Glucose is the only fuel used during maximal exercise.
Fats (foods they come in, recommended daily intake, what they are stored as, when they are the bodies main source of fuel)
- Butter, cheese and full-cream dairy products, oils, nuts and fatty meats
Recommended daily intake-25-30%
Converted to free fatty acids and stored as adipose tissue at various sites
They are the body’s main source of fuel at rest and during prolonged submaximal exercise. They provide the highest yield at the slowest rate, as they require more oxygen then carbohydrates to be broken down.
Proteins
Used mainly for growth and repair.
‘Last resort’ fuel source
Energy sytems
- The ATP-PC system
- The Anaerobic Glycolysis system
- Aerobic systems
ATP-PC energy system
- anaerobic (no oxygen required)
- Most rapidly available source of ATP as it is stored in the muscles and has simple reactions meaning it has the fastest rate.
- Breaks down phosphocreatine to resynthesise ATP anaerobically
- PC splits releasing energy which is used to resynthesise ATP stores.
How long does ATP-PC energy system last (at maximal intensity)
ATP stores= 2-3sec
PC stores= 10sec
Dominant ATP supplier during activity between 1-5 seconds
Increased contribution of ATP during exercise bouts that last for 0-10secs
How can PC stores be replenished
They can be replenished via 3 minutes of passive recovery, or an intensity low enough not to call on PC (oxygen required to resynthesise)
30sec of passive recovery= 70% of stores
3min= 98%
10min= 100%
Anaerobic glycolysis energy system (how it works+ yield/rate)
- Glycogen is broken down in the absence of oxygen producing pyruvic acid which is converted to lactic acid
- supplies ATP at a slower rate but a greater yield (almost x2) than the ATP-PC system. It requires longer and more complex chemical reactions which cause it to have a slower rate.
increased contribution during activity between 5-60sec (10-75sec)(depending on aerobic fitness)
By products of the anaerobic glycolysis system (how they affect muscular performance)
A byproduct of lactate is hydrogen ions which make the muscle more acidic (reduces pH). The increase in acidity reduces glycolysis and causes muscular discomfort and an inability for them to contract maximally. This is caused as the pH decrease affects rate of reaction as the enzymes move further away from their optimal pH. This is a safety mechanism that prevents the cells from being destroyed in extremely acidic conditions.
How does recovery help reduce H+ ions
In recovery when sufficient oxygen is available, H+ ions combine with pyruvate to form lactate which then gets reconverted into glycogen in the liver. This is why an activity recovery is necessary for events with anaerobic glycolysis usage as it keeps the heart rate up and ensures that oxygen is available for removal of wastes.
Aerobic energy system
Requires oxygen
CHOs preferred fuel during exercise and Fats are preferred during rest are broken down to release energy
Slowest rate of ATP resynthesis as it requires the most chemical reactions
the yield of ATP production is 30-50 times that of the anaerobic energy system combined
Increased contribution from any activity lasting longer than 75sec
Aerobic byproducts
When using CHOs pyruvic acid is produced and further broken down producing CO2, H2O & ATP (via Kreb’s cycle)
Further breakdown via the electron transport chain. It requires hydrogen ions and oxygen, producing water and heat.
