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The breakdown of ATP provides
the energy currency for all forms
of biological work
Bioenergetics
Muscle cell Energy systems
Food Molecules
Mechanical Work
ATP
Energy stored during the
breakdown of food is used
to manufacture a chemical
compound
Contains a lot of energy
Stored in muscle cells
Cells use the energy released
from the breakdown of ATP to
perform work
Bioenergetics
Chemical to Mechanical Energy
ATP is broken down enzymatically to adenosine
diphosphate (ADP) and inorganic phosphate (Pi) to yield
energy for muscle contraction
Bioenergetics
Energy for muscle contraction
ATP
ENERGY
ADP Pi
Release of the myosin cross bridge from actin requires binding of ATP. After ATP binds it is split to
ADP and inorganic phosphate the energy derived from this reaction is used to cock the cross bridge
in preparation for the power stroke. The power stroke is initiated when the myosin cross bridge
binds to actin. The cycle begins again when another ATP binds to myosin
Bioenergetics
Metabolic Systems
1. Phosphagen system
2. Glycolysis
3. Aerobic system
Each system provides energy to make ATP
Bioenergetics
Phosphagen System
Immediate source of energy that can be used to
add a phosphate to ADP
Creatinephosphate
Bioenergetics
Glycolysis
Lactate
Acetyl-CoA
Glucose
G-6-PGlycogen
Occurs inside the cytosol
Glucose 6-phosphate – from
muscle glycogen or from blood
glucose is converted to lactate or
pyruvate producing ATP
Bioenergetics
Krebs/TCA cycle
Occurs in the mitochondria
and involves a series of 8
chemical reactions that
begins and ends with
Oxaloacetate
Bioenergetics
Phosphagen System
Cis-Aconitate
Citrate
Succinyl-CoA
-ketoglutarate Isocitrate
Malate
Fumarate
Succinate
4 H
4 H
4 H
4 H
2 ATP
Oxaloacetate
Acetyl-CoA
Cis-Aconitate
Citrate
Succinyl-CoA
-ketoglutarate Isocitrate
Malate
Fumarate
Succinate
4 H
4 H
4 H
4 H
2 ATP
Cis-Aconitate
Citrate
Succinyl-CoA
-ketoglutarate Isocitrate
Malate
Fumarate
Succinate
4 H
4 H
4 H
4 H
2 ATP
Oxaloacetate
Acetyl-CoA
Oxaloacetate
Acetyl-CoA
Bioenergetics
Electron Transport Chain
Within the mitochorndria
oxidative phosphorylation
occurs in the electron
transport chain (ETC) which
is situated on the inner
mitochorndrial membrane
Bioenergetics
Phosphagen System
NADH
Dehydrogenase
Cytochrome
b-c1
Cytochrome
oxidase ATP
Synthase
The ETC, the final metabolic pathway; it proceeds as a series of chemical reactions in the
mitochondria that transfer electrons from hydrogen atoms NAD and FAD to Oxygen. The
electrochemical energy releases is coupled to the formation of ATP from ADP and Pi
Acetyl-CoA
Mitochondria(engine of the cell)
Bioenergetics
Chemical Energy
Lactate
Acetyl-CoA
Glucose
G-6-PGlycogen
Glucose 36 ATP
KrebsCycle
‘Oxidation’
Glycogen 37 ATP Fat 129 ATP
Fat