Download - ATP ENERGY PRODUCTION
ATP ENERGY PRODUCTION
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Energy
• The body needs a constant supply of energy to perform every day tasks such as respiration and digestion.
• Energy is the capacity to perform work and is measured in joules or calories.
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Calorie, Joule and Watt
• Calorie is the amount of heat energy needed to raise the temperature of 1 gram of water through 1oC.
• A Kilocalorie (kCal)is 1000 calories.• Joule = 4.2 kCal.• A Watt is equivalent to the use of one joule per
second.• Power is the work performed per unit of time
and is measured in watts.
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Work
• Work is defined as force x distance.• It can be measured in calories and joules. Food• Food is chemical energy.• It is converted into movement (kinetic
energy).• Or is stored as potential energy.
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Energy release in the body
• Energy release in the body is complicated.• There is only one usable form of energy in the
body – adenosine triphosphate (ATP).• All food we eat has to be converted into ATP.• ATP is a high energy phosphate compound made
up of adenosine and 3 phosphates.• The bonds that hold the compound together are a
source of a lot of potential energy.• ATP = adenosine-phosphate-phosphate-phosphate
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• When a compound is broken down( the bonds between the molecules are broken) the energy is released.
• ATP is broken down to adenosine diphosphate (ADP) and free phosphate, releasing the stored energy.
• ATP → ADP + P + Energy• The energy released from the breakdown of
ATP to ADP and P is converted to kinetic and heat energy.
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Methods of ATP production• Once ATP has been broken down to release energy it has
to be put back.• There are three ways that this is achieved in the human
body:• 1 The phosphocreatine system (ATP/PC) or alactic system.• 2 The lactic acid system or anaerobic glycolysis.• 3 The aerobic system.• Each method is good at supplying energy for particular
energy demands and duration.• Systems 1 and 2 are anaerobic they take place without
oxygen• System 3 is aerobic: it requires oxygen to work.
The ATP Molecule
Adenosine
Adenosine
Energy
Adenosine Triphosphate (ATP)
The breakdown of ATP:
PP
P
PP P
ATP = ADP + energy for biological work + P
(ADP = Adenosine Diphosphate)
Energy for cellular function
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ATP Production by Phosphocreatine or Alactic System
• Phosphocreatine is a high- energy phosphate compound.
• It is found in the sarcoplasm of the muscle.• Potential energy is stored in the bonds of the
compound. Phosphocreatine → P+ Creatine + Energy creatine kinase
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• Creatine kinase is activated when the level of ADP in the muscle cell increases.
• It is when the stores of ATP start to diminish.• The energy released by the breakdown of PC is
used to convert ADP to ATP.• Energy has to be liberated by the breakdown
of PC before ATP can be formed.• Stores of PC in the muscles are enough to
sustain all out effort for about ten seconds.
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• This is the only system capable of producing ATP quickly.
• During activities that demand large amounts of energy over a short period of time
• As PC is stored in the muscle it is readily accessible as an energy source.
• Energy for ATP can be obtained extremely quickly.
• No fatiguing by products are released.
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ATP production by the lactic acid system or Glycolysis
• Also anaerobic taking place in the sarcoplasm.• The energy needed comes from the food we
eat.• It involves the partial breakdown of glucose.• Breakdown of PC does not rely on the
availability of oxygen.• It is much more complex than Phosphocreatine.• It therefore stores more energy.
The Glycolytic System
•Involves the breakdown (lysis) of glucose by glycolytic
enzymes.
•Glucose comes from the digestion of carbs & breakdown of
glycogen during glycogenolysis.
•Glycogen is made from glucose during glycogenisis.
•Glycolysis produces pyruvic acid which is then converted to
lactic acid in the absence of oxygen.
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• Glucose is broken down anaerobically (in absence of oxygen).
• Because there is no O2 lactic acid is formed.• Breakdown of bonds in glucose release
energy.• The energy is used to synthesise ATP.• The lactic acid system takes longer to produce
energy than the ATP/PC system.• It supplies energy for high intensity activities
for about a minute.• The 400m is a good example.
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Outline of Lactic Acid System (anaerobi glycolysis)Production of energy for resynthesis of ATP
ADENOSINE TRIPHOSPHATE (ATP)
Formed in the breaking down of GLUCOSE
This in turn is broken down by a chemical reaction to give
PYRUVIC ACID
If there is insufficient oxygen LACTIC ACID accumulates
This causes FATIGUE in the muscles. & H+
LACTIC ACID SYSTEM
Glycogen made from glucose from digested food present in all cells of the body – muscles, liver
When glycogen breaks down it releases pyruvic acid and energy.
This energy is used to re-build ATP from ADP and P
This system is anaerobic – no O2
Pyruvic acid is easily removed when O2 is available
No O2 = Pyruvic acid is converted into lactic acid
Muscles fail to contract fully - fatigue
• The lactic acid builds up due to the shortage of O2 = oxygen debt needs to be paid back once exercise has finished.
• Takes about 20 – 60 mins to remove accumulated lactic acid after maximal exercise
• Lactic acid build-up makes muscles feel tired & painful exercising anaerobically can only be done for short periods of time.
Accumulation of Lactic Acid
Lactic acid affects muscular contraction by:
1. Inhibiting the secretion of calcium that enables the
coupling of actin and myosin protein filaments = protein
filaments cant attach to each other. The sliding of the muscle
protein filaments = not possible.
2. Inhibiting the action of the glycolytic enzymes = glucose not
being broken down. Glucose is the food fuel for both
anaerobic and aerobic glycolysis.
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Fatigue • When glycogen is broken down anaerobically
lactic acid is produced.• If lactic acid accumulates it lowers the pH (H+).• pH affects action of phosphofructokinase.• It also affects lipoprotein kinase that breaks
down fat.• The body’s ability to synthesise ATP is
temporarily reduced causing fatigue.
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Production of ATP using the Aerobic System
• Needs oxygen.• At the onset of exercise there isn’t enough O2
to break down food fuels.• So the 2 anaerobic systems are used.• As heart rate and rate of ventilation increase
more oxygen gets to the working muscles.• Within 1-2 minutes the muscles are being
supplied with enough O2 to allow effective aerobic respiration.
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Stage 1:Aerobic glycolysis• Aerobic glcolysis is the same as anaerobic
glycolysis.• Glucose is broken down to pyruvic acid.• As O2 is now present the reaction can proceed
further than in anaerobic glycolysis.• Lactic acid is not produced.• Two molecules of ATP are synthesised at this
stage.
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Stage 2: The TCA/Citric acid/Krebs’ Cycle
• The pyruvic acid produced in the 1st stage diffuses into the matrix of the mitochondria.
• A complex cyclical series of reactions now occurs.• During the cycle three important things happen:1.carbon dioxide is formed.2.oxidation takes place-hydrogen is removed from
the compound.3.Sufficient energy is released to synthesis 2
molecules of ATP.
The Kreb’s Cycle.• The pyruvic acid is taken by the enzyme acetyl
CoA into the Kreb’s cycle in the mitochondria
Glycogen
Pyruvic acid2 ATP
Lactic acid
Kreb’s cycle
*Sarcoplasm*
*Mitochondria*
2 ATP2CO2 Removed via lungs
Acetyl CoA
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Stage 3:The Electron transport chain/electron transport system
• The H2 atoms removed in stage 2 are transported by coenzymes to the inner membrane of the mitochondria.
• The electrons are passed along by electron carries combining with O2 and H2 ions to form water.
• Energy is released which combines ADP with phosphate to form ATP.
• The energy yield from the electron transport chain forms 34 molecules of ATP.
• The total yield of ATP from aerobic respiration is therefore 38 molecules of ATP.
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• The aerobic system of synthesising ATP is the most efficient.
• The byproducts (CO2 and H2O) are easily expelled from the body.
• However the reactions involved in this system depend on the availability of O2.
Electron transport chain
• Involves water (perspiration), heat and large amounts of ATP being released.
• Aerobic system breaks down carbs rather than fats to release energy (fats produce more ATP than carbs but require more O2 to produce equivalent amount of ATP.)
• Aerobic system is fatigue resistant = primary source of ATP for endurance activities.
• Aerobic production of ATP happens in the mitochondria.
The ETC.
Krebs cycle
Hydrogen
ETC
O2
H2O34ATP
Mitochondria matrix.
Mitochondria cristae
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Characteristics of the 3 Energy Systems
Energy System
Aerobic/ Anaerobic
Fuel/ Energy Source
By-product Exercise intensity Duration Sporting
Examples NOTES
ATP/ PC Anaerobic ATP/ PC Creatine High (Flat Out)
10 – 15 Seconds
Sprinting, athletic field events, weight-lifting.
Small muscular stores of ATP and PC are exhausted quickly leading to a rapid decline in immediate energy.
Lactic Acid
Anaerobic GlycogenGlucose
Pyruvic Acid/ Lactic Acid
High Intensity
Up to 3 minutes
400m800mRacket sports.
Lactic acid is a by-product and can cause rapid fatigue.
Aerobic Aerobic Fat/ glucose mixture
Water/ CO2 Low 3 minutes onwards
Long distance running/ cycling.
This system is limited by availability of O2