LEWIS: Aerobic Energy System Flashcards Preview

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Flashcards in LEWIS: Aerobic Energy System Deck (109):
1

In order to move our muscles need to

contract

2

For our muscles to contract they need a supply of

energy

3

The energy we need for muscle contractions is supplied to us in the form of food which is broken down within cells to release energy that is used to form

chemicals

4

These chemicals can be broken down to release the energy stored within them, therefore the body uses

chemical energy

5

Muscles use the chemical energy stored in specific compounds to move. The body then converts the energy found into a form that it can

handle

6

The immediately/directly usable form of chemical energy for muscular activity is

Adenosine Triphosphate (ATP)

7

It's the body's job to transfer the chemical energy stored in the food we eat into the suable energy found in ATP. Energy is released when ATP is

broken down

8

Energy is required when ATP is

resynthesised

9

The breakdown of ATP releases

adenosine diphosphate (ADP) and phosphate (P)

10

Equation for ATP breakdown:

ATP -> ADP + P + ENERGY

11

The body then rebuilds/re-synthesises ATP from the breakdown products:

ADP + P + ENERGY -> ATP

12

When a muscle fibre needs ATP to supply the energy for the fibre to contract, that ATP has to be

produced or resynthesised right away

13

Able to resynthesise ATP from 3 different types of chemical reactions that take place within the muscle cells:

2 depend on the food we eat
3rd relies on phosphocreatine found in muscles

14

Everyday tasks uses energy that involves chemical reactions that use

oxygen

15

Using oxygen in order to produce the ATP that we need is said to involve

aerobic processes

16

We obtain our energy from the food we

eat

17

6 classes of food - 3 which can be used as energy sources:

Fats
Carbohydrates
Proteins

18

Carbohydrates broken down/digested to

glucose

19

Glucose is the main form of carbohydrate found in the body and dissolves in

blood plasma

20

Fats broken down/digested to

Fatty acids and glycerol

21

Fats are stored in cells that make up a special tissue mainly found under the skin and surrounding major organs known as

adipose tissue

22

When fats are stored and used as an energy source they are known as

triglycerides

23

Proteins are digested into

amino acids

24

These energy sources once broken down then enter the blood system and become available for the

body

25

Carbohydrate -> glucose dissolves into the blood plasma and circulates around the body in the blood system
This glucose may be used by

all cells and tissues, including working muscles, as an energy source for the resynthesis of ATP

26

Any excess glucose that enters the blood following digestion of a meal may be stored in

muscles and liver as glycogen

27

glycogen may also be used as a source of ATP by muscles as it is

easily and quickly broken down into glucose

28

When our liver and muscle glycogen stores are full, any excess glucose from digestion is converted into fat droplets and stored in

adipose tissue

29

The glycerol and fatty acids (called free fatty acids when in the blood) that are formed during fat digestion may be used directly from the blood, but most are converted back into

fats and stored as triglycerides in adipose tissue

30

Glycerol may be converted into glucose which is what happens when the diet is lacking in carbohydrate or when

glycogen stores have been depleted as may happen during long-duration exercise that demands continuous energy supplies (e.g. a marathon)

31

Amino acids (breakdown products of proteins) are usually used by the body for

growth and repair

32

Unlike carbohydrates and fats, amino acids cannot be stored, instead they are

broken down by the liver, and the nitrogen-containing part of the molecule is excreted as urea

33

When we exercise, the part of the amino acid left after the urea has been removed may be

converted into glucose or used in some stage of the energy production system

34

Interconversions of the energy sources are mainly a function of the

liver

35

Some conversions are easier than others, thus the liver readily converts excess glucose into fat, but less readily into

glycogen

36

Reverse reactions, the conversion of glycogen into glucose is easily done in the liver, but less readily accomplished in

muscles

37

Resting 1/2 - 2/3 of our energy comes from

fats

38

Resting 1/2 - 1/3 of our energy comes from

carbohydrates

39

Ratio of energy sources changes when exercising, but the exact proportions depends on many factors such as:

-Type of exercise
-Type of diet
-Performer's fitness level
-Type of muscle fibres involved in the exercise

40

Provided that the supply of oxygen to the muscles can be maintained, the complete breakdown of glycogen and glucose to provide energy for ATP resynthesis is

possible

41

Breakdown of glycogen and glucose using oxygen is said to be an

aerobic process

42

Exercising muscles can obtain carbs from

glycogen stored in the liver and muscles
glucose circulating in the blood
fat either circulating in blood or stored in adipose tissue

43

Most of the glycogen stored in the liver is used for

an emergency supply for the brain in case blood glucose levels fall

44

The use of protein as an energy source is fairly complex but also happens to be small enough to be

negligible

45

Problems with using glycogen as an energy source are:

-stores are limited
-muscle fatigue occurs rapidly when stores are depleted

46

Muscle glycogen stores are fully depleted with any exercise that lasts longer than

2 hours

47

During recovery from exercise, there is an initial rapid replacement of used glycogen, but complete recovery may take more than

24 hours

48

The longer an exercise lasts (more endurance based it is) the more we tend to use

fats as an energy source

49

Fats may only be used as an energy source if

oxygen is present

50

The use of fat as an energy source therefore depends on the supply of oxygen to the

muscles

51

In slow-twitch muscle fibres, especially, fat is the main source of energy during most activities that last

longer than 1 hour

52

Because training increases the body's capacity to supply oxygen to the working muscles, it also increases the muscle fibres' ability to use

fats as an energy source

53

Glycerol and fatty acids need to be supplied by the blood when used as

energy sources

54

Glycerol released from fat stores may enter the energy pathways or be converted into

glucose for use in the normal way

55

Adipose tissue releases free fatty acids, which are transported around the blood, bound to

proteins

56

Molecules of glucose, glycogen and fats are completely broken down in the presence of

oxygen

57

Complete breakdown of carbs and fats produces:

-carbon and oxygen (CO2)
-Hydrogen and oxygen (Water)
-energy for ATP resynthesis

58

Majority of ATP production is confined to

mitochondria

59

Muscle cells tend to have large numbers of

mitochondria

60

The aerobic production of ATP has 4 advantages over other systems:

-No fatigue by-products
-Abundant supply of starting chemicals
-36-38 ATP molecules gained from 1 ATP
-Slow twitch fibres provide a continuous supply of energy over a long period of time

61

1st stage of aerobic system:

Glycolysis

62

Glycolysis involves:

-Glycogen broken down into glucose
-Production of pyruvic acid (pyruvate)

63

Glycolysis takes place in the

sarcoplasm of muscle cells

64

During glycolysis how many ATP molecules are made for each molecule of glucose?

4

65

Pyruvic acid formed during glycolysis is added to the enzyme

coenzyme A (CoA)

66

Pyruvic acid + CoA =

acetyl CoA to allow it to enter the next stage

67

2nd stage of aerobic system =

Krebs cycle

68

Krebs cycle occurs within the

mitochondria

69

The Krebs cycle consists of a series of 8 enzyme-driven reactions that oxidise acetyl CoA to

carbon dioxide

70

(KC) Hydrogen atoms that are part of acetyl CoA are transferred to chemicals called

hydrogen carriers

71

(KC) Hydrogen carriers eventually enter the next stage of aerobic metabolism known as

the electron transfer chain

72

In the ETC a series of carrier molecules are involved in the oxidising of the hydrogen contained within the hydrogen carriers, producing water as a by-product and generating a large supply of ATP:

34 molecules of ATP for each glucose molecule

73

Pyruvic acid from glycolysis eventually becomes converted into CO2 and water and large amounts of energy are released in the form of ATP - this process requires large amounts of

oxygen for its completion

74

Fatty acids from the breakdown of triglycerides are themselves broken down within the sarcoplasm by a process called

beta-oxidation

75

Beta-oxidation is the breakdown of fats into

acetyl CoA within the sarcoplasm

76

(BETA-OXIDATION) acetyl CoA can then enter the KC and eventually the ETC for

ATP production

77

During exercise, reliance on fats diminishes dramatically in explosive sports, but in endurance events the mixed use of

fats and carbs = important

78

Mix of carbs and fats depends on 4 factors:

intensity
duration
athlete's level of fitness
diet and nutritional status

79

1st stage of fat break down is the beta-oxidation of these free fatty acids into acetyl CoA. This 'prepares' the fatty acid for entry into the

mitochondria

80

Final result of fat break down once fatty acid is in mitochondria =

water and carbon dioxide are produced
Energy is released from ATP resynthesis

81

If exercise is slow continuous activity, fats can be the

main energy source

82

Fat requires more oxygen for breakdown than glucose as it has more carbon atoms in its structure. Aerobic processes convert those carbon atoms into

co2

83

Limited oxygen supply =

limits KC and ETC

84

Limited oxygen supply occurs during

intensive exercise

85

When there is not enough o2 available, the preferred energy source =

glucose

86

Appropriate training increases the body's ability to

take in oxygen to the muscles and therefore increase the ability to use fat for energy

87

Limitations of fat as an energy source:

-Unavailable in limited oxygen supplies (explosive exercise)
-Fat stores = excess non-functional weight

88

Endurance training increases the body's ability to

release free fatty acids from their fat stores - trained performer can use more fats for energy than untrained

89

Breakdown of fats requires carbs presence as they enable the KC within the mitochondria to

operate

90

Demand for energy remains high during prolonged, continuous exercise, glycogen stores become depleted and the breakdown of fats will slow because of the

lack of carbs

91

When glycogen stores have depleted and KC slows as a result as well as ATP resynthesis, it is known as

'hitting the wall'

92

Disadvantage of fats:

-Can restrict joint movement

93

11 Adaptations due to training:

-cardiac hypertrophy
-increased resting stroke volume
-decreased resting HR
-reduced exercising and maximal heart rate
-increased blood volume and haemoglobin
-increased muscle stores of glycogen and triglycerides
-increased myoglobin content in muscles
-increased capillarisation of muscle
-increased number and size of mitochondria
-increased concentrations of oxidative enzymes
-beta-oxidation becomes more efficient

94

As a result of adaptations following training what increases:

VO2 max

95

VO2 max is the

maximum amount of oxygen consumed and utilised per minute

96

VO2 max is also known as

aerobic capacity

97

fuels used in
GLYCOLYSIS =
KREBS CYCLE =


GLYCOGEN/GLUCOSE
FATTY ACIDS

98

Molecules of ATP produced in:
GLYCOLYSIS =
KREBS CYCLE =
ELECTRON TRANSPORT CHAIN =


2
2
34

99

2 Drawbacks of aerobic energy system:

-presence of oxygen = lower intensity or 3 minute threshold
-relies heavily on glycogen stores initially

100

training methods for aerobic energy system:

-continuous training (60-80% max HR)
-low intensity fartlek training

101

What sports use aerobic energy system:

1500m
marathon

102

When we exercise, or even when we are at rest, our bodies are using oxygen to

Resynthesise ATP

103

ATP is needed for:

The heart
The muscles of respiration to contract
Keep brain functioning

104

The amount of oxygen used by the body to produce ATP is called

Oxygen consumption

105

When we begin to exercise we need more ATP and therefore use more oxygen so our

Oxygen consumption increases

106

When we exercise, or even when we are at rest, our bodies are using oxygen to

Resynthesise ATP

107

ATP is needed for:

The heart
The muscles of respiration to contract
Keep brain functioning

108

The amount of oxygen used by the body to produce ATP is called

Oxygen consumption

109

When we begin to exercise we need more ATP and therefore use more oxygen so our

Oxygen consumption increases