LEWIS: Aerobic Energy System Flashcards
(109 cards)
1
Q
In order to move our muscles need to
A
contract
2
Q
For our muscles to contract they need a supply of
A
energy
3
Q
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
A
chemicals
4
Q
These chemicals can be broken down to release the energy stored within them, therefore the body uses
A
chemical energy
5
Q
Muscles use the chemical energy stored in specific compounds to move. The body then converts the energy found into a form that it can
A
handle
6
Q
The immediately/directly usable form of chemical energy for muscular activity is
A
Adenosine Triphosphate (ATP)
7
Q
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
A
broken down
8
Q
Energy is required when ATP is
A
resynthesised
9
Q
The breakdown of ATP releases
A
adenosine diphosphate (ADP) and phosphate (P)
10
Q
Equation for ATP breakdown:
A
ATP -> ADP + P + ENERGY
11
Q
The body then rebuilds/re-synthesises ATP from the breakdown products:
A
ADP + P + ENERGY -> ATP
12
Q
When a muscle fibre needs ATP to supply the energy for the fibre to contract, that ATP has to be
A
produced or resynthesised right away
13
Q
Able to resynthesise ATP from 3 different types of chemical reactions that take place within the muscle cells:
A
2 depend on the food we eat
3rd relies on phosphocreatine found in muscles
14
Q
Everyday tasks uses energy that involves chemical reactions that use
A
oxygen
15
Q
Using oxygen in order to produce the ATP that we need is said to involve
A
aerobic processes
16
Q
We obtain our energy from the food we
A
eat
17
Q
6 classes of food - 3 which can be used as energy sources:
A
Fats
Carbohydrates
Proteins
18
Q
Carbohydrates broken down/digested to
A
glucose
19
Q
Glucose is the main form of carbohydrate found in the body and dissolves in
A
blood plasma
20
Q
Fats broken down/digested to
A
Fatty acids and glycerol
21
Q
Fats are stored in cells that make up a special tissue mainly found under the skin and surrounding major organs known as
A
adipose tissue
22
Q
When fats are stored and used as an energy source they are known as
A
triglycerides
23
Q
Proteins are digested into
A
amino acids
24
Q
These energy sources once broken down then enter the blood system and become available for the
A
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
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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
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Krebs cycle occurs within the
mitochondria
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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
