Energy Systems Flashcards

1
Q

where does the energy we use for muscle contractions come from

A

adenosine triphosphate (ATP). the energy that is stored in ATP is released by breaking down the bonds that hold this compound together. enzymes are uysed to break down the bonds.

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2
Q

what enzyme breaks down ATP into ADP + Pi

A

ATPase

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3
Q

The conversion of fuel into energy takes place in one of three pathways which are

A
  • aerobic system
  • the ATP-PC system
  • the anaerobic glycolytic system
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4
Q

When is the aerobic system the preferred pathway

A

When the exercise intensity is low and oxygen availability is high

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5
Q

What are the by-products of the aerobic system

A
  • Carbon Dioxide
  • water
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6
Q

The complete oxidation of glucose can produce how many ATPs (aerobic systems)

A

38 ATPs

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7
Q

The aerobic system has 3 stages which are

A
  • Glycolysis
  • Kreb’s Cycle
  • Electron Transport Chain
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8
Q

What is glycolysis

A
  • the breakdown of glucose into pyruvate
  • takes place in the sarcoplasm
  • for every molecule of glucose undergoing glycolysis, a net of two molecules of ATP is formed.
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9
Q

What happens to the pyruvate so it can move to the next stage of the system

A

The pyruvic acid is oxidised into two acetyl groups and is then carried into Kreb’s cycle by coenzyme A

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10
Q

Where does the coenzyme a come from (aerobic system)

A

The products of the metabolism of fats and proteins are reduced to the molecule acetyl coenzyme a.

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11
Q

what is the kreb’s cycle

A

the two acetyl groups (formerly pyruvic acid) diffuse into the matrix of the mitochondria. and they undergo a complex cycle of reactions

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12
Q

describe what happens in the kreb’s cycle

A
  • the two acetyl groups combine with oxaloacetic acid to from citric acid.
  • hydrogen is removed from the citric acid and the now rearranged form of citric acid undergoes oxidative carboxylation (simply meaning carbon and hydrogen are given off)
  • the carbon forms carbon dioxide which is transported to the lungs and breathed out
  • the hydrogen is transported to the electron transport chain
  • the result of these reactions result in the production of 2 ATP molecules
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13
Q

what is the electron transport chain

A
  • the hydrogen from the krebs cycle is carried to the electron transport chain by hydrogen carriers
  • occurs in the cristae of the mitochondria
  • the hydrogen splits into hydrogen and electrons and they are charged with potential energy
  • the hydrogen ions are oxidised to from water while the hydrogen electrons provide the energy to re-synthesise ATP
  • throughout this process 34 ATP are formed
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14
Q

other than glucose what other fuels can the aerobic system use

A
  • fats in the form of fatty acids and proteins in the from of amino acids
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15
Q

what is beta oxidation

A
  • when stored fat is broken down into glycerol and free fatty acids
  • the fatty acids then undergo a process called beta oxidation where it is converted to coenzyme a (the entry molecule for the krebs cycle)
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16
Q

what can produce more ATP from one molecule: fatty acids or glucose

A
  • fatty acids
17
Q

what is the predominant energy source for the aerobic system

A

in long duration, low intensity exercise, fatty acids are the predominant energy source however does depend on the performer

18
Q

what are the advantages of the aerobic system

A
  • more ATP can be produced (36 molecules)
  • there are no fatiguing by-products
  • lots of glycogen and triglyceride stores so exercise can last for a long time
19
Q

what are the disadvantages of the aerobic system

A
  • complicated system so cannot be used straight away. it takes a while for enough oxygen to become available to meet the demands of the activity and ensure glycogen and fatty acids are completely broken down
  • fatty acids transportation to muscles is low and also require 15% more oxygen to be broken down than glycogen
20
Q

what does it mean if something is reduced

A
  • it means the molecules has gained hydrogen or lost oxygen
21
Q

what does it mean if something is oxidised

A
  • it means the molecule has gained oxygen or lost hydrogen
22
Q

what is the fuel of the atp-pc system

A

phosphocreatine (PC)

23
Q

what is phosphocreatine

A

an energy rich phosphate compound found in the sarcoplasm adn can be broken down quickly and easily to release energy and re-synthesise ATP

24
Q

what activities may the ATP-PC system be useful for

A

single maximum movements such as long lump take-off or shot putt

25
Q

what is the atp-pc system

A
  • anaerobic process
  • re-sythesises ATP when the enzyme creatine kinase detects high levels of ADP
26
Q

what is the equation for how PC releases energy

A

PC –> Pi + C + energy

this energy is then used to convert ADP to ATP in a coupled reaction

Energy –> + Pi + ADP –> ATP

27
Q

For every PC how much ATP do you get

A

1 molecule of ATP

28
Q

what are the advantages of the ATP-PC system

A
  • ATP can be re-synthesised rapidly
  • phosphocreatine stores can be-synthesised quickly
  • no fatiguing by products
  • possible to extend the time the atp-pc system can be utilised through use of creatine supplementation
29
Q

what are the disadvantages of the atp-pc system

A
  • there is only a limited supply of phosphocreatine in the muscle cell, only can last for 10 seconds
  • one mole of ATP can be re-synthesised for every mole of PC
  • PC re-synthesis can only take place in the presence of oxygen
30
Q

what is the anaerobic glycolytic system

A

an energy system that provides energy for high-intensity exercise and for longer than the atp-pc system

31
Q

what is said to be the duration of the anaerobic glycolytic system

A
  • depends on the individuals fitness and how high the intensity of the exercise is
  • e.g. a 400m athlete who has jus run the 400m wont be albe to do it again at the same pace because working flat out to exhaustion means the system will last much shorter time
  • usually lasts up to 2-3 minutes
32
Q

how does the anaerobic glycolytic system work

A
  • starts with anaerobic glycolysis (where PC stroes are low and the enzyme glycogen phosphorylase breaks down the glycogen into glucose and then further broken down into pyruvic acid by phosphofructokinase where the product of this reaction is 2 ATP)
  • the pyruvic acid is then further broken down into lactic acid by the enzyme lactate dehydrogenase
33
Q

where does the anaerobic glycolytic system take place

A

sarcoplasm

34
Q

what is the net result of atp produced from this system

A

2 molecules of ATP for 1 molecule glucose

35
Q

what are the advantages of the anaerobic glycolytic system

A
  • ATP can be re-synthesised quickly due to very few chemical reactions
  • lasts longer than the ATP-PC system
  • in the presence of oxygen, lactic acid can be converted back into the liver glycogen or used as a fuel through oxidation into carbon dioxide and water
  • it can be used to produce an extra burst of energy
36
Q

what are the disadvantages of the anaerobic glycolytic system

A
  • lactic acid as the by-product means enzymes become denatured and prevents them from increasing the rate of reaction
  • only a small amount of energy can be released from glycogen under anaerobic conditions
37
Q
A