Energy and Enzymes Section 2.4

Chemical Reactions Reactions create energy transfer Energy – the ability to do work or cause changes Chemical reaction: Reactants  Products Ex. H2O + CO2  H2CO3 Reactions create energy transfer Exergonic Reactions - __________ free energy

Chemical Reactions Reactions create energy transfer Energy – the ability to do work or cause changes Chemical reaction: Reactants  Products Ex. H2O + CO2  H2CO3 Reactions create energy transfer Exergonic Reactions - ___release_ free energy Endergonic Reactions - _________ free energy

Chemical Reactions Reactions create energy transfer Energy – the ability to do work or cause changes Chemical reaction: Reactants  Products Ex. H2O + CO2  H2CO3 Reactions create energy transfer Exergonic Reactions - ___release_ free energy Endergonic Reactions - __absorb_ free energy

Activation energy – energy needed to start a reaction. Catalysts – chemical substances that reduce the amount of activation energy needed for a reaction. Ex. _______

Enzymes Enzymes speed up reactions by lowering the activation energy needed for a reaction Enzyme binds to substrate Enzymes are substrate-specific (1E = 1S) (like a lock and key)

Factors that affect Enzyme Activity Temperature Concentration pH Regulatory molecules