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Role of ATP

ATP
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All living organisms gain energy by the
process of RESPIRATION
Glucose is broken down in controlled steps
by enzymes
Small amounts of energy are released at
each stage
This energy is used to produce
ADENOSINE TRIPHOSPHATE or ATP
The ‘universal energy currency’

Structure
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ATP is a nucleotide consisting of:
an organic base (adenine)
a 5 carbon sugar (ribose)
a sequence of 3 linked phosphate groups

Importance
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Uncontrolled release of energy from
glucose would result in a temperature
increase that would destroy cells
Living organisms release energy gradually
to produce ATP
ADP + Pi  ATP

Importance
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The reaction is ENDERGONIC as energy
is used
30kJ mol-1 is needed to add one
phosphate molecule
Phosphate groups are held in place by
high-energy bonds
So ATP is a short-term energy store

Importance
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ATP can be hydrolysed to release energy
when required
When ATP is broken down to ADP and Pi
the reaction is described as EXERGONIC
as energy is released
The reaction is catalysed by the enzyme
ATPase
30kJ mol-1 of energy is given out

Importance
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ATP  ADP + Pi + 30kJ mol-1

The addition of phosphate to ADP is called
PHOSPHORYLATION

Advantages of ATP
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Only one enzyme needed to release its
energy
Releases energy in small amounts
Provides a common source of energy for
many different chemical reactions

ATP is not stored – it gets synthesised
when required

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ATP provides the energy for:
active transport
muscle contraction
synthesis of materials in cells
nerve transmission



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