Anatomy & Physiology - Energy Systems Flashcards
The way in which energy is provided depends on:
- Intensity
- Duration
Where does the energy come from for muscle contractions:
- Adenosine Triphosphate (ATP)
- ATP is the only usable energy in our body
What does ATP consist of:
- 1 molecule of Adenosine
- 3 phosphates
How is energy released from an ATP molecule:
- Energy is released by breaking down bonds. Enzymes are used to break the ATP compound
What Enzyme breaks down ATP:
- ATPase is the enzyme that breaks down ATP and leaves ADP (Adenosine Diphosphate) and an Inorganic Phosphate (Pi)
What is energy released in the form of:
- Energy is released in the form of HEAT (Exothermic reaction)
What happens when the bond is broken:
- When the ATP becomes ADP because of the breaking of a bond the spare phosphorus atom, can no longer be used as it is a dead battery
What would happen if we didn’t recharge the atom:
- Without recharging it and turning it back into an ATP compound, our body would cease to function in a matter of seconds
What is ATP Resynthesis:
- ATP within muscle fibers are used up very quickly (2 seconds) and therefore needs to be replenished immediately
- Resynthesis of ATP is done through joining of ADP and a single phosphate. This energy regeneration is only possible through one of three energy systems
What are the “Fuels” that enable ATP Resynthesis:
- Glycogen
- Fats
- Protein
- Phosphocreatine
What is Glycogen’s role in ATP Resynthesis:
- Stored in the muscles and the liver. It’s converted into glucose before being used for ATP resynthesis this can be done both aerobically and anaerobically
What is Fats role in ATP Resynthesis:
- At rest 2/3 of energy requirements are met through breaking down fatty acids. Rich in energy, but require large amounts of O2 to break down. Transport of fats is slow and only used during low intensity
What is Proteins role in ATP Resynthesis:
- Contribute the least to the energy yield, only 15. Used the carbohydrates and fat stores are running low
What is Phosphocreatine’s role in ATP Resynthesis:
- A chemical stored within the muscle cell. Used within the first 10 seconds of intense exercise
What are the 3 energy systems that generate ATP:
- ATP-PC system
- Anaerobic glycolytic system
- Aerobic system
What energy system is used for HIGH intensity exercise:
- Anaerobic glycolytic system
What energy system is used for LOW intensity exercise:
- Aerobic system
How long does ATP last for:
- 2 seconds
What is phosphocreatine (PC):
- Energy rich chemical produced naturally by the body
Where is Phosphocreatine found:
- In the Sarcoplasm of the muscles
What enzyme detects high levels ADP:
- Creatine Kinase
What does Creatine Kinase do:
- Breaks down PC to P + C to release energy for ADP to combine with the extra phosphate to resynthesis ATP
What is the relationship between ATP and PC:
- A Coupled Reaction
What is Coupled reaction:
- When energy required by one process is supplied by another
How energy is released from PC:
- Breakdown of phosphocreatine releases energy and the energy is used to convert ADP to ATP and this is known as a Coupled reaction
How many PC is broken down to make how many ATP:
- Every 1 molecule of PC broken down, 1 ATP is resynthesised
How long will the ATP-PC provide energy for:
- 8-10 seconds
How much can PC store after 3 minutes:
- 98% after 3 minute of rest
What is needed for PC to recover:
- It can only replenish itself during low intensity exercise
- And when oxygen is present
What sporting examples require ATP-PC system:
- 100m sprint
- Weight lifting
- Long jump
What time of activities is ATP-PC used for:
- High intensity, short duration activity lasting between 5-10 seconds
4 Advantages of the ATP-PC system :
- No harmful by-products
- ATP can be resynthesised rapidly
- Pc stores replenished within 3 minutes
- ATP-PC system can be extended through the use of a creatine supplement
3 Disadvantages of the ATP-PC system:
- Short duration energy depletes quickly (8-10 seconds)
- 1 ATP molecule re-synthesised for 1 molecule of PC
- PC synthesis can only take place in the presence of oxygen
What type of energy does the Anaerobic Glycolytic system provide:
- Provides energy for high intensity activity (longer than the ATP-PC system)
What does the duration of the Anaerobic Glycolytic system depend on:
- Depends on the fitness of the athlete and the intensity of the activity
What happens to the Anaerobic Glycolytic system when PC depletes:
- Once PC is depleted (around 10seconds) the anaerobic glycolytic system takes over and generates ATP from the breakdown of the fuel glucose.
What is the ‘fuel’ glucose supplied from for the anaerobic glycolytic system:
- Glucose is supplied from the digestion of carbohydrates and is stored in the muscles and the liver as glycogen
What enzyme breaks glycogen into glucose:
- When the PC stores are low/depleted the enzyme Glycogen Phosphorylase is activated to break down the glycogen into glucose
Where does the breakdown of glucose take place:
- Glucose in the absence of oxygen takes place in the sarcoplasm of the muscle cell and is called Anaerobic glycolysis and causes the production of Pyruvic acid
What is glucose broken down to resynthesis:
- 2 molecules of ATP
For glucose to breakdown what enzyme needs to be present:
- Phosophfructokinase
What happens because of the process being anaerobic:
- The pyretic acid is further broken down into lactic acid by the enzyme lactate dehydrogenase (LDH)
What happens the longer exercise continues:
- The higher the rise in lactic acid and PH levels (Lactic acid is a strong acid that causes pain&fatigue)
When can lactic acid be removed from the body:
- The build up in the muscles and cannot be removed until the body is respiring aerobically
What does Lactic acid do:
- Denatures the enzymes involved in respiration meaning the muscle cells become slower at resynthesising ATP
What is OBLA:
- Onset of blood lactate accumulation. Point at which lactate starts to accumulate in the muscles/blood
What is EPOC:
- Excess post exercise oxygen consumption
What does Glycogen Phosphorylase do:
- Breaks glycogen into glucose
What does Phosphofructokinase do:
- Breaks glucose dow into pyruvic acid
What does Lactate Dehydrogenase do:
- Breaks pyruvic acid down into lactic acid
A sporting example that requires the anaerobic glycolytic system:
- Counter attack in football - As glycolic ATP resynthesis will continue for 3 minutes but peak at 1 minute
4 advantages of anaerobic glycolytic system:
- ATP can be resynthesised quickly (due to few chemical reactions being needed + lasts long)
- 2/3 minutes without oxygen for energy
- This energy system is useful for producing an extra burst of energy (sprint finish in a race)
- If oxygen, is present lactic acid is converted back into glycogen
3 Disadvantage of anaerobic glycolytic system:
- Lactic acid is a by-prodcut of this system
- Only a small amount of energy is released from glycogen while under anaerobic conditions
- Small energy yield (2 ATP) and the rate of glucose depletion is rapid
Where does the aerobic system take place:
- Takes place in the mitochondria (generate the most most of energy)
What type of exercise does it occur at:
- Low intensity exercise in the presence of oxygen
Where does it release stored energy from:
- Releases stored energy from muscles glycogen and fats to resynthesis ATP
What does the Aerobic system rely on the presence off:
- Oxygen
What does the oxygen do for the Aerobic system:
- Completely breakdown stores energy (from muscle glycogen , fats and proteins) into carbon dioxide + water + energy
Why is the aerobic system the most efficient way of resynthesising ATP:
- The energy yield is high - 1 molecule of glucose yields 36 molecules of ATP and this process will continue until energy stores run out (in the anaerobic glycolytic process yield is 2 molecules of ATP) So 38 ATP in total
What happens to the fats (fatty acids) when broken down:
- They’re reduced to the molecule acetyl coenzyme A. This molecule enters the Kreb cycle (stage 2 Aerobic system)
What happens when the proteins are broken down:
- They too are reduced to the molecule acetyl coenzyme A. This molecule enters the Kreb cycle (stage 2 Aerobic system)
What are the 3 stages of the Aerobic system:
- Glycolysis
- The Kreb cycle
- The Electron Transport Chain
What is Glycolysis:
- The breakdown of glucose into pyruvic acid
What is the Kreb cycle:
- A series of cyclical chemical reactions for the oxidation of acetyl coenzyme A to take place
What is The Electron Transport Chain:
- Involves a series of chemical reactions in the cristae of the mitochondria where hydrogen is oxidised tower and ATP are produced
Aerobic system - Stage 1 - Glycolysis:
- This is the same process as anaerobic glycolysis but in the presence of OXYGEN during the final stage of glycolysis determines if the aerobic energy system is used. If OXYGEN is present the pyruvic acid is converted to Acetyl coenzyme A in the mitochondria opposed to remaining in the muscle sarcoplasm and being converted into lactic acid
(2 ATP molecules are resynthesised)
Aerobic system - Stage 2 - Kreb cycle:
- The pyruvic acid doesn’t turn into lactic acid so the pyruvic acid is oxidised into Acetyl coenzyme A. And then enters the Kreb cycle which occurs in the mitochondria and this mitochondria produces high levels of energy
What does Acetyl coenzyme A do:
- Moves the mitochondria within the muscle cell where the remaining stages are activated
What happens once the pyruvic acid diffuses:
- Once the pyruvic acid is diffused into the MATRIX of the mitochondria a complex cycle of reactions occur in a process called the Krebs cycle
What happens as a result of the Kreb cycle:
- The Acetyl coenzyme A combines with oxaloacetic acid and this forms citric acid. The citric acid produced then undergoes oxidative carboxylation
What is produced due to the Kreb cycle:
- CO2 (Breathed out) + H2o + H+ ions OR hydrogen atoms + 2 ATP
What is the Kreb cycle a simple mechanism for:
- Removing H atoms (H+) from the complex chemicals involved , leaving carbon ad oxygen to form carbon dioxide
These Hydrogen atoms (ions) are taken to the electron transport chain
Aerobic system - Stage 3 - The Electron Transport Chain:
- Hydrogen is carried to the electron transport chain by hydrogen carriers and there are 2 coenzymes that join with the hydrogen atoms
What are the 2 coenzymes that join with the hydrogen atoms:
- NAD + FAD and join the hydrogen atoms to form NADH + FADH
Where does the electron transport chain take place:
- Cristae of mitochondria
What does hydrogen split into:
- Hydrogen ions + Electrons and these are charged with potential energy
What are the hydrogen ions combined with:
- Hydrogen ions are combined with OXYGEN to form a bi-product of WATER, while providing energy to resynthesise ATP
How many ATP are formed through out the electron transport chain process:
- 34 ATP molecules are formed
As an equation what is the overall yield from the Aerobic system:
- 2 ATP - Glycolysis + 2 ATP - Kreb cycle + 34 ATP - Electron Transport Chain = 38 ATP total
Aerobic system - Free fatty acids - Beta oxidation
- Stored fats must be broken down first from triglycerides into glycerol and free fatty acids. The free fatty acids and glycerol go through a process called Beta oxidation forming Oxaloacetic acid which combines with Acetyl coenzyme A. Which can then enter the Kreb cycle.
What is Beta oxidation:
- The process of using free fatty acids to produce Acetyl coenzyme A, which is the substance that can be admitted into the Kreb cycle
How much ATP can be made from 1 molecule of fatty acids:
- More can be made from fatty acids than from one molecules of glycogen but the intensity must be LOW because they require a larger presence of OXYGEN. This is why long duration exercise FATTY ACIDS will be the predominant ENERGY source.
4 Advantages of the Aerobic system:
1) More ATP produced than Anaerobic system
2) Really high energy yield (38 ATP)
3) No fatiguing bi-product (CO2 + water which are exhaled)
4) Plenty of glycogen and triglyceride stores
3 Disadvantages of the Aerobic system:
1) This system can only be used during sub maximal activities
2) It can take oxygen a while to become available
3) Fatty acid transportation to muscle sites are slow
What happens during high intensity exercise:
1) The body relies on anaerobic respiration
2) It uses the ATP-PC system and anaerobic glycolysis
3) Only produce energy for 8-10 seconds - ATP-PC
Anaerobic glycolysis - 3minutes
What happens to lactic acid when broken down:
- Lactic acid is broken-down creating lactate
What does Lactic acid release when broken down:
- Releases hydrogen ions (H+) the remaining compound combines with sodium ions (NA+) or potassium ions (K+) which forms salt lactate
What happens when lactate accumulates:
- More hydrogen ions are present.
- This increase in hydrogen ions causes an increase in acidity
What does the increase in acidity do:
- Slows down enzyme activity so the glycogen cannot be broken down as effectively
- Fatigue then sets in
What is lactate threshold:
- The point at which lactic acid starts to quickly accumulate in the blood
What is the accumulation of lactate in the blood known as:
- OBLA (Onset of blood lactate accumulation)
What is OBLA:
- The point at which lactate starts to accumulate in the blood (starts at 4 mol/liter above resting levels)
What is the relationship between Lactate threshold and V02 Max:
- The higher the V02 Max the more the delay in lactic acid build up as V02 Max increases so does the lactate threshold
What happens if you are fit to your Lactate threshold:
- The fitter you are the higher the lactate threshold as a percentage of our V02 Max and hence the harder we can work
What are the 5 factors affecting Lactate accumulation:
1) Intensity of exercise
2) Fitness of performer
3) Muscle fiber types
4) Rate of blood lactate removal
5) Respiratory exchange rate
What does buffering mean:
- A process which enables them to remove lactate at a greater rate and maintain acidity levels in the blood and muscles
What adaptations occur due to training:
1) Number + size of mitochondria
2) Associated oxidative enzymes
3) Increased capillary density
4) More myoglobin
What energy system will be utilized during long duration/low intensity:
- Aerobic system
What is Oxygen consumption:
- The amount of oxygen we use t produce ATP. Often referred to as V02
What is V02 Max:
- The maximum volume of oxygen taken up and used by the muscles per minute
What happens when we start to exercise (sub-maximal oxygen deficit):
- There is not enough oxygen present to provide energy aerobically so energy is provided anaerobically to satisfy the increase demand for energy
Why does this happen:
- The circulatory system and the mitochondria take time to respond to the rate of aerobic respiration (Sub maximal oxygen deficit)
What is EPOC:
- The total volume of oxygen that is consumed during recover above that which would have been consumed at rest during the same period. It enables the body to fully recover, and return to its pre-exercise state
What 2 stages is EPOC split into:
1) Fast component
2) Slow component
What happens during the first stage of EPOC: Fast component
- Alactacid component uses the extra oxygen that is taken in to restore ATP and PC and re-saturate myoglobin with oxygen
What happens during the second stage of EPOC: Slow component
- Lactacid component the slow component continues on from the fast component but begins as soon as exercise finishes
What are the 4 main processes of the Slow component during EPOC:
1) Lactic acid removal
2) Maintenance of breathing and heart rate
3) Glycogen replenishment 4) Increase in body temperature
What does Lactic acid removal do:
- Increase in oxygen consumption which allows lactic acid to be converted back into pyruvate via the aerobic pathway (kern cycle) into carbon dioxide, water and energy
- 25% of the pyruvic acid is removed into glucose + small amounts into protein
- Transports the lactic acid within the blood to the liver, to then convert it back into blood
- The lactic acid is removed in sweat + urine
What is maintaining breathing rate:
- Extra oxygen provides energy for the respiratory muscles + cardiac muscles
It assists recovery:
- Extra oxygen replenishes ATP + PC stores
- Re-saturates myoglobin
- Removes lactic acid
What is glycogen replenishment:
- This is dependent on when and how much carbohydrate is consumed after exercise (could take several days after a marathon)
- Within the 1st hour after high duration, low intensity we can restore a significant amount of glucose
How do we restore a significant amount of glycogen:
- Glycogen can be stored as lactic acid which is then converted back to blood glucose and glycogen in the liver via the Cori cycle
For optimal recovery:
1) carbohydrates + proteins (ratio 3:1 or 4:1)
2) Chocolate milk
What is increase in body temperature:
- When temperature remains high, respiratory rates remain high
- Helps the athlete take in more oxygen during recover. But extra oxygen is needed tp fuel the increase in temperature in the body unit it returns to normal
