Energy for exercise Flashcards
Definition of ATP
Adenosine triphosphate
Energy currency of the body
Only usable form of energy for muscular contraction
What is the structure of ATP?
Compound of Adenosine and 3 phosphates
High energy bonds between phosphates are potential energy
Where is ATP stored?
Muscle sarcoplasm
What enzyme breaks down ATP?
ATPase
What is left after ATP is broken down?
ADP
Pi (inorganic P - no energy link)
Energy used for muscle contraction
How much ATP is in the body?
Only enough for 2-3 seconds
What type of reaction is the breaking down of ATP?
Exothermic
What type of reaction is the resynthesis of ATP?
Endothermic
How do we resynthesise ATP?
Energy from energy systems + ADP + Pi
Definition of an enzyme
A catalyst that speeds up the rate of a chemical reaction
Definition of ADP
A compound formed when the terminal phosphate bond is removed from ATP
Definition of Exothermic
A reaction the releases energy
Definition of Endothermic
A reaction that takes in energy
What is a coupled reaction?
A reaction where the energy released in the first reaction is used in the secind
What is the energy continuum?
The relative contribution and interaction of the energy systems to ATP resynthesis depending on intensity/duration of exercise
What 9 things do you need to know about each energy system?
Type of reaction (aerobic/anaerobic) Food fuel used Site of reaction Enzyme ATP yield Stages of system By products Intensity/duration Fibre types it links to
What type of reaction is the ATP-PC system?
Anaerobic
What fuel is used in the ATP-PC system?
Phosphocreatine
Where does the reaction occur in the ATP-PC system?
Muscle sarcoplasm
What enzyme is used in the ATP-PC system?
Creatine kinase
What is the ATP yield of the ATP-PC system?
1 ATP
What are the stages of the ATP-PC system?
PC broken down by creatine kinase into Pi+C+ energy
Energy is coupled to resynthesis of 1ATP
What are the by products of the ATP-PC system?
Creatine and Pi
No fatiguing by products
What is the intensity/duration when using the ATP-PC system?
Very high
2-10 seconds
Which fibre types are linked to the ATP-PC system?
Fast glycolytic type 2b
Advantages of the ATP-PC system
No oxygen needed
Simple compound, quickly broken down, ATP resynthesis is quick
PC resynthesises quickly so recovery is short (50% in 30 seconds, 100% in 2-3 minutes)
No fatiguing by products
Readily available (stored in sarcoplasm)
Disadvantages of ATP-PC system
Only small amounts in sarcoplasm
Poor ATP yield (1 per PC molecule)
Only 8-10 seconds of activity is possible
What type of reaction is the glycolytic system?
Anaerobic
What fuels are used in the glycolytic system?
Glycogen
Glucose
Where does the reaction occur for the glycolytic system?
Muscle sarcoplasm
What enzymes are used in the glycolytic system?
GPP
PFK
LDH
What is the ATP yield of the glycolytic system?
2 per glycogen/glucose molecule
What are the stages of the glycolytic system?
Glycogen broken down into glucose by GPP which is broken down into pyruvic acid by PFK, this releases energy to resynthesise 2ATP
Pyruvic acid is broken down into Lactic acid by LDH when there’s no oxygen
What is the by product of the glycolytic system?
Lactic acid
What does lactic acid do?
Lowers pH
Inhibits enzymes
Stimulates pain receptors
Causes muscle pain/fatigue
What is the intensity/duration when using the glycolytic system?
High
Short 10 seconds - 3 minutes
Advantages of the glycolytic system
Large supplies of glycogen/glucose
No oxygen needed
Relatively few reactions so relatively quick
Allows high intensity work for up to 3 minutes
Resynthesise double ATP as ATP-PC system
Lactic acid converted back to glycogen in cori cycle
Disadvantages of the glycolytic system
Lactic acid is a fatiguing by product
Lower ATP yield than aerobic system
Recovery rate is slow (60 minutes for lactate levels to return to resting values after strenuous activity)
What is the name given to the process of the glycolytic system?
Anaerobic glycolysis
What is another name for the glycolytic system?
Lactic acid system
What are the 3 stages of the aerobic system?
Aerobic glycolysis
Kreb’s cycle
Electron transport chain
What type of reaction is the aerobic system?
Aerobic
What fuels are used in the aerobic system?
Glycogen
Glucose
Fats (lipids)
What are the sites of the three stages of the aerobic system?
Muscle sarcoplasm (AG)
Matrix of mitochondria (KC)
Cristae of mitochondria (ETC)
What enzymes are involved in the aerobic system?
GPP/PFK
Coenzyme A
What is the overall ATP yield of the the aerobic system?
38 from 1 molecule of glycogen/glucose
What is the aerobic glycolysis stage of the aerobic system?
Glycogen broken down by GPP into glucose which is broken down by PFK into pyruvic acid which releases energy to resynthesise 2ATP
What is the Kreb’s cycle stage of the aerobic system?
Pyruvic acid broken down by coenzyme A into Acetyl coA which joins to oxaloacetic acid. 4 things then happen: Carbon dioxide breaks off Hydrogen breaks off Energy is released to resynthesise 2ATP Oxaloacetic acid is regenerated
What is the electron transport chain stage of the aerobic system?
The hydrogen atoms splits into:
A hydrogen ion which combines with oxygen to form water
An electron which is carried by electron carriers NADH and FADH through the cristae folds to release energy to resynthesise 34ATP
What are the by products of the aerobic system?
Carbon dioxide
Water
What is the intensity/duration if using the aerobic system?
Low/submaximal Very long (more than 3 minutes)
How do you recover after using the aerobic system?
Ingesting carbohydrates to replenish glycogen stores
What fibre type is used when using the aerobic system?
Slow twitch type 1
What fibre types are used when using the glycolytic system?
Fast glycolytic type 2a and 2b
What are the advantages of the aerobic system?
Large supplies of glycogen/glucose
No-fatiguing by products
Good oxygen supply guarantees efficient ATP resynthesis
Can resynthesise 38 ATP per molecule of glycogen/glucose
Provides energy for long duration (3 minutes to 3 hours)
What are the disadvantages of the aerobic system?
More complex reactions, delay for oxygen transport so slower.
Can’t immediately be used to resynthesise ATP
Requires oxygen (decrease work rate before OBLA)
Only low intensity
Takes 2-3 minutes for enough oxygen to be available
What is an energy profile?
A model that shows the % contribution of each energy system to ATP resynthesis.
Is an energy system ever not being used at all?
No all are always working it is just that one system is predominant
What is a threshold?
The point at which the predominant energy system switches from one to another.
What are the 4 factors affecting energy system interplay?
Intensity of exercise
Duration of exercise
Recovery periods
Fitness levels
How long is ATP the predominant source of energy?
2-3 seconds
How long is the ATP-PC system the predominant system?
from 2 seconds to 8-10 seconds
How long is the glycolytic system the predominant one?
10-180 seconds
How long is the aerobic system the predominant one?
180 seconds onwards
What is intermittent exercise?
Exercise where the intensity repeatedly varies between maximal to submaximal to rest
Benefits of intermittent exercise?
Improves VO2 max
Delays thresholds
Delays fatigue
Definition of VO2 max
The maximum volume of Oxygen that can be used by the body in 1 minute
What is the aerobic system used for in recovery periods in intermittent exercise?
Replenish ATP and PC stores - 50% in 30 seconds, 100% in 3 minutes
Resaturate myoglobin and haemoglobin
Decrease lactic acid levels
What are longer rest period (eg half time) in intermittent exercise used for?
Rehydration/replenishment of glycogen stores eg by drinking isotonic drinks
Allow performer to perform repeated high intensity bouts and delay fatigue.
Advantages of increased aerobic fitness
More efficient CV and respiratory system so more oxygen transported to muscle
Increased VO2 max
Delay fatigue, lactate threshold and OBLA due to quicker removal of lactic acid - athlete can work at higher intensity within aerobic system.
Can switch to aerobic system sooner
Advantages of increased anaerobic system
Increased PC and glycogen stores
Increased tolerance to lactic acid
Delayed threshold of anaerobic systems allowing athlete to work at a high intensity for longer.
