Energy Systems

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Energy Systems
Metabolism
Adenosine Triphosphate (ATP)
Aerobic/Anerobic Energy Systems
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Metabolism
Metabolism -
all the chemical reactions occurring within the
body where cells release energy from food
Basal metabolic rate (BMR) -
the rate at which the body uses energy when
resting
A resting body is not Homer Simpson resting as
it is still busy
Repairing tissue
Pumping blood
Regulating internal body temperature
Digesting food
It can be likened to an idling car, burning fuel
but going nowhere!
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Basal Metabolic Rate
BMR differs for each individual. Several factors
contribute to individual differences in BMR
Age Amt. of Body Fat Gender Diet Body
temperature Stress Hormones Activity
level
BMR highest during growing years drops 2/yr
every decade gt20
Higher body fat percentage ? lower BMR
Women have a lower BMR than men (higher body fat
)
Dieting lowers BMR as body conserves energy
(survival mechanism)
BMR increases with increasing temperature
Stress increases activity of Symp. Nervous System
? higher BMR
Thyroxine from thyroid gland and epinephrine both
increase BMR
Regular exercise increases catabolism of fat at
rest and during exercise, therefore increasing BMR
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Metabolism Volcabulary
Anabolism -
the process of building compounds
the process of breaking down compounds (releasing
energy)
Catabolism -
Adenosine Triphosphate -
the immediate source of energy for body
functions, especially muscle contractions
(ATP)
Phosphocreatine -
a high energy compound used to resynthesize ATP
(PCr)
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Catabolism
Stage 1
Large food compounds (complex carbohydrates,
triglycerides(fats), proteins) are broken down
into smaller units (simple sugars, fatty acids
and amino acids). These smaller units are
delivered to working cells like muscle cells by
the bloodstream.
Stage 2
The smaller compounds are broken down further to
CO2 and H2O inside the cells. Large amounts of
energy are released to power the cell. This
energy is called ATP. ATP is the energy created
from breaking down carbohydrates, fats, and
proteins.
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Adenosine Triphosphate (ATP)
ATP is the immediate source of energy for body
functions, especially muscle contractions.

• there is only a small amount of ATP stored with
  the muscle cell

• the total amount of ATP in the body at any one
  time is 3 ounces

• stored ATP provides energy to perform maximally
  for about 2 6 sec

• ATP is continuously recycled within each cell

• depletion of stored ATP stimulates the breakdown
  of stored

nutrients to provide energy for ATP synthesis

• there are 3 systems used to recycle ATP

• type, length, and intensity of activity
  determine which system is

used to synthesize ATP
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Adenosine Triphosphate (ATP)
ATP

Pi
Pi
Pi
Adenosine
Energy
Energy
Energy
Energy
ATPase
_
_
_
_
_
_
Pi
Adenosine
Pi
Pi
?
Adenosine
Pi
Pi

Pi

Pi
ATP ? ADP Pi Energy
ATPase is the enzyme that causes the phosphate to
split from the ATP molecule, releasing a large
amount of energy!
Phosphorylation -
Storing of energy by addition of a phosphate
group
Oxidative Phosphorylation -
Synthesis of ATP from ADP by addition of a
phosphate group with the aid of oxygen
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DING DING DING - BELL RINGER!!!
1. BMR is a measure of what?
2. Name 3 factors that influence BMR.
3. Briefly describe the two stages of Catabolism
(food).
4. What does phosphorylation mean?
5. The amt. of ATP stored in the body at any one
time is ____________________
6. Stored ATP will sustain maximal muscle
contraction for ________________ (how long)
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Adenosine Triphosphate (ATP)
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Energy (ATP) Functions
1. Growth and repair of body tissues
2. Muscle contractions (sliding filaments)
3. Build/repair muscle after exercise or injury
4. Active transport of substances across cell
membranes e.g. glucose, Ca2
5. Nerve transmission
6. Circulation
7. Digestion
8. Secretion by glands
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Bioenergetic Conversion
Through bioenergetic conversion of the three
following key nutrients, the body obtains the
energy (ATP) it needs to function
Three key energy nutrients
1. Carbohydrates
2. Fats
3. Proteins
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Carbohydrate Metabolism
Carbohydrates

• sources are plants (vegetables, fruits) and
  grains (bread, pasta)

• forms sugars and starches (saccharides)

• 4.1 calories of energy per gram

• glucose (blood sugar) is most common
  monosaccharide found in foods and digestive
  tract as a product of the breakdown of complex
  carbohydrates (starches)

• glycogen polysaccharide formed by joining of
  glucose molecules that is stored in skeletal
  muscle and the liver for energy source

• glycogen stores depleted ( few hours),
  synthesis is ongoing

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Energy Systems
There are two energy systems for resynthesizing
ATP
1. Anaerobic

• without the use of oxygen (O2)

• none of its metabolic activity will involve
  oxygen

2. Aerobic

• in the presence of oxygen (O2)

• all of its metabolic activity will involve oxygen

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Metabolic Pathways
Within the two energy systems there are three
metabolic pathways for resynthesizing ATP
Anaerobic
Note Lactic refers to a metabolic by-product,
lactic acid. (Alactic no lactic acid produced)
1. ATP-PC (anaerobic alactic)
2. Glycolysis (anaerobic lactic)
Aerobic
1. Cellular respiration
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ATP - PC System

• known as the Anaerobic alactic system

Location Cytoplasm/sarcoplasm

• uses stored ATP and creatine phosphate

• last 0 15 seconds (onset of activity or quick,
  powerful exercises)

• powers Fast Twitch type IIb fibres

e.g. Diving, shot put, 100m sprinting,
weightlifting

• no by-products produced

PCr
Creatine kinase
Creatine

Pi

Energy
ATP
ADP

Pi

Energy
During first few seconds of intense activity ATP
levels are constant. As PCr depletes, ATP cannot
continue to be resynthesized quickly enough,
leaving very low levels of PCr ATP at
exhaustion.
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ATP - PC System
Yield 1 molecule ATP
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Anaerobic Lactic System - Glycolysis
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Anaerobic Lactic System

• known as glycolysis (breaking apart glucose or
  glycogen)

• takes place in the cytoplasm/sarcoplasm of cell

• stored ATP and creatine phosphate have been
  depleted

• carbohydrates glucose, glycogen and starch are
  catabolized to fuel ATP resynthesis

• Lactic acid is a by-product that accumulates in
  the blood causing temporary but painful muscle
  fatigue

• lasts 15 sec to 2 minutes (short duration, high
  intensity exercise)

• powers Fast Twitch type IIa, b muscle fibres

• NO OXYGEN NECESSARY!

e.g. 400 800 m sprints, soccer, basketball,
hockey (start, stop sports)
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Anaerobic Lactic System
Yield 2 molecules ATP/molecule of glucose
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Aerobic System - Cellular Respiration
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Aerobic System
Cellular respiration is the process by which
carbohydrates and fats are catabolized to CO2 and
H2O, in the presence of oxygen, liberating energy
that is used to fuel ATP resynthesis.
process also called oxidative phosphorylation

• system averts lactic acid production responsible
  for muscle fatigue and shutdown

• takes place in the mitochondria

• most efficient and predominant source of ATP
  production (95)

• powers Slow Twitch type I muscle fibres (low
  intensity)

• lasts from 2 min to several hours

• depletion of glycogen in muscles results in
  fatigue

• increased carbohydrate intake in diet delays
  fatigue and improves endurance in these activities

e.g. sitting, standing, walking, jogging,
distance swimming, biking,
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Aerobic System
32 ATP
36
Yield 36 molecules ATP/molecule of glucose
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Fat Metabolism
Fats

• found in both animal and plant sources

• 9 calories of energy per gram

• ideal source of energy for prolonged exercise

• 4 types of fats fatty acids, triglycerides,
  phospholipids, steroids

• triglycerides stored in the body are broken down
  (lipolysis) into glycerol and three fatty acid
  chains

• fatty acids are converted into acetyl-CoA by
  beta oxidation (mitochondria), they then enter
  the Krebs cycle and become an energy source for
  ATP production

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Protein Metabolism
Protein

• made up of different combinations of 20 amino
  acids

• 4.3 calories of energy per gram

• no protein reserves, all protein is functional
  as muscles, enzymes at all times

• to be used as energy, protein has to be broken
  down into its amino acids which are then used to
  make glycogen, acetyl-CoA, etc

• proteins only called upon as energy source when
  all other supplies are depleted (e.g. endurance
  events)

• similar to short-term starvation

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The Cori Cycle and Lactic Acid
The Cori cycle is the process where lactic acid
created in the muscle during anaerobic activity
is transported to the liver where it is converted
back to pyruvate and then to glucose
(gluconeogenesis). It is then released back into
the blood to be used in the future as an energy
source.
Note Because the process requires energy (ATP)
to proceed, it takes place in the 30 40
mins following activity when the O2 demand for
ATP resynthesis can be met.
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Energy Systems A Comparison
15 sec to 2 mins
2 mins to hours
0 15 sec
No
No
Yes
No
Yes
No
Glycogen Fat
PCr Phosphocreatine
Glycogen
None
Lactic acid
CO2 H2O
Type IIB
Type IIA B
Type I
Med - High
Low - Med
High
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Energy Systems and Sports
Sports vary widely in both intensity and
duration. Analyze the following activities, and
access which is their predominant energy system.

• cross country skiing

• bowling

A An A An L/A An L An An L An L A An An
An An/A An An An A An An An L An An L/A

• alpine skiing

• badminton

• cross country running

• javelin throw

• basketball

• 50 m swimming

• volleyball

• discus

• curling

• 2 km swimming

• dancing

• 100 m sprint

• 800 m running

• wrestling

• 5 km rollerblading

• 200 m sprint

• football

• golf

• high jump

• soccer

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THE END!