Zusammenfassung der Ressource
Energy Systems
- Energy Transfer in the body
- The energy we use
for muscle
contractions comes
from adenosine
triphosphate (ATP)
- The energy that is stored in ATP is released by
breaking down bonds. Enzymes are used to
break down the compound, ATP-ase is used
leaving ADP and Pi
- The Body constantly rebuild ATP by
converting ADP and Pi back into ATP.
- We re-synthesise ATP through three
different types of chemical reaction in the
muscle cell; Fuelled by either food, or a
chemical called phosphocreatine. Or finally
the conversion of theses fuels through one
of the three energy systems
- Aerobic
System
- Used when
intensity of
exercise is low
and oxygen
supply is high
e.g. long
distance
running
- Stage 1; Glycolysis
- Takes place
in the
sarcoplasm
of the
muscle
- It is the break
down of
glucose into
pyruvic acid
- For every molecule
of glucose
undergoing
glycolysis, a net of
two molecules of
ATP are produced.
- Before the pyruvic acid produced can
enter the next stage, it splits into two
acetyl groups and is the carried into
the kerb cycle by coenzyme A
- Stage 2: The kerb cycle
- Acetyl coenzyme A
combines with
oxaloacetic acid,
forming citric acid.
- Hydrogen is removed from citric
acid and the rearranged form of
citric acid undergoes 'oxidative
carboxylation'. (hydrogen is given
off)
- The carbon forms CO2, which is
transported to the lungs and
breathed out and the hydrogen is
taken to the electron transport
chain
- Fats can enter the Kerb cycle.
- Stored fats are
broken down into
glycerol and free
fatty acids for
transportation in
the blood
- These fatty acids
under go 'Beta
oxidation'
- Beta oxidation: A
process where fatty
acids are broken down
to generate acetyl-
Coenzyme A which
enters the kerb cycle.
- 2 ATP
molecules
are
produced
- Stage 3: Electron Transport Chain
- Hydrogen is
transported into
the ETC by
hydrogen carriers.
- This occurs in
the cristae of
the
mitochondria
- The hydrogen splits
into hydrogen ions
and electrons and
they are charged
with potential
energy
- The hydrogen ions are
oxidised to form water,
while the hydrogen
electrons provide the
energy needed to
re-synthesis ATP
- 34
Molecules
of ATP are
produced
- ATP-PC system
- Uses phosphocreatine (PC)
as fuel. It can be broken
down quickly and easily to
release energy to
re-synthesise ATP
- Anaerobic Process
- It re-synthesises ATP when the
enzyme creatine kinase
detects high levels of ADP
- It breaks down PC in the
muscles into phosphate (pi)
and creatine (c), releasing
energy
- PC---> Pi + C + energy
- The energy is then used to
convert ADP to ATP in a
coupled reaction
- Energy ---> Pi + ADP ----> ATP
- Short term lactate anaerobic system
- Provides energy for
high-intensity exercise,
longer than the
ATP-PC system
- How long the system
lasts depends on the
fitness of the
individual
- When the PC stores are low, the
enzyme glycogen phosphorylase is
activated to break down glycogen
into glucose, which is further broken
down into pyruvic acid by the
enzyme phosphofructokinase
- Anaerobic glycolysis