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

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  Releasing Free Energy means chopping off the terminal phosphate from ATP  Condensation is required to put the phosphate onto ADP.  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.

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