ATP
Storing and Releasing Free Energy
Chemical Energy



Life processes require a constant supply of
energy.
Nutrients supply organisms with energy and
raw materials
The energy contained within the nutrient
molecules is known as chemical energy.
Chemical Energy


Bond energy between the atoms of a nutrient
molecule is known as chemical energy.
Organisms ingest nutrients for chemical
energy and raw materials.
Cellular Respiration

Chemical energy found in nutrients gets
converted into free energy (energy that is
available to do work) by a process known as
cellular respiration.
Free Energy


Energy that is immediately available for cells
is known as free energy.
The ATP molecule is a molecule that stores
and releases free energy.
ATP



The letters ATP stand for Adenosine
Triphosphate.
Adenosine = Adenine (a nitrogen base) and
Ribose (a five carbon sugar)
Triphosphate = Three phosphates bonded
together in a straight line.
Structure of ATP Molecule
Structure of ATP Molecule
Examine the ATP Molecule



Look for the nitrogen
base called adenine. It
is a double-ringed
structure
Look for the 5 carbon
sugar called ribose
Examine the three
phosphates bonded in a
straight line.
Releasing Free Energy



The Bonds between the phosphates contain
free energy.
Chop off the terminal phosphate and free
energy is released.
A-P-P~P. The terminal phosphate contains
the most energy.
Equation for Releasing Free Energy

A-P-P~P
A-P-P + free energy + P
Notice that ATP
(Adenosine
triphosphate) becomes
ADP (Adenosine
Diphosphate)
Storing Free Energy



When the cell has free energy that needs to be
temporarily stored, ATP is formed from ADP.
ADP stands for Adenosine DiPhosphate
Putting a phosphate back onto ATP stores free
energy.
Equation for Storing Free Energy

A-P-P + P + Free energy
A-P-P~P
Chemical Reactions: Condensation and
Hydrolysis

Storing Free Energy
means putting a
phosphate onto ADP

Condensation is
required to put the
phosphate onto ADP.

Releasing Free Energy
means chopping off the
terminal phosphate
from ATP

Hydrolysis is required
to chop off a phosphate
from ATP
Hydrolysis of ATP

Hydrolysis of ATP is used by the cell to
provide the energy needed to drive the
chemical reactions that enable an organism to
function.
Dehydration Synthesis aka
Condensation

A Condensation (aka Dehydration Synthesis)
reaction is required to store free energy onto
an ADP molecule forming ATP.
ATP

A large macromolecule that stores and
releases free energy.
Keep Studying Biochemistry