another form of potential energy

energy stored in bonds between molecules

some energy is lost during transfer as heat energy into the environment 

this esceped energy is now useless

"energy in"

require energy and result in more free energy than the reactants had 

ex: ADP-->ATP

"energy out"

release energy so products have less free energy than the reactants 

ex: ATP-->ADP

composed of adenosine, ribose, and 3 phosphate groups

ATP is earned through exergonic reactions

ATP is spent through endergonic reactions

when phosphate links to ADP to make ATP 

when this bond is broken, energy is released

• catalysts that speed up reactions
• do this by lowering the activation energy 
• are very selective about the reactants

1. help substrates get along
2. orient substrates in position favoring to reaction
3. induce changes in reactants shape (induced fit model)
4. shutting out water

1. increase temp, decrease reaction rate
2. reactions function best at pH 7 
3. enzyme inactivated when change in osmotic pressure or change in charges

control enzyme activity 

bind to regulatory site NOT active site

using negative feedback inhibition, shuts down its own synthesis to prevent overproduction