CHEMICAL REACTIONS and ENZYMES

What are Chemical Reactions? Occur when substances are TRANSFORMED into new substances by breaking and forming CHEMICAL BONDS. 2 H2O2  2 H2O + O2 Starting molecules/atoms are referred to as REACTANTS (Things which react). Ending molecules/atoms are referred to as PRODUCTS (Things which are produced).

General Formula REACTANTS  PRODUCTS Since chemical bonds store energy, what happens when we break them? What happens when we form them?

Exothermic Reactions Feel HOT because they RELEASE energy/heat into their surroundings Breakdown of macromolecules.

Endothermic Reactions Feel COLD because they ABSORB energy/heat from their surroundings. Formation of macromolecules.

Why Biochemical Reactions are NON-SPONTANEOUS Reactants must HIT in the right place. The CONCENTRATION of reactants is generally not high. Reactions depend on TEMPERATURE MOST IMPORTANTLY = To join two molecules, existing bonds must be BROKEN, which requires ENERGY. The energy required to start, or activate, a reaction is called the ACTIVATION ENERGY

Modified Reaction Potential Energy Diagrams Most biochemical reactions require a great deal of activation energy, which makes them run very SLOWLY.

How do we perform chemical Reactions when the Activation energy is too high? A CATALYST is something that speeds up reactions by LOWERING the energy of activation. ENZYMES are special proteins that act as catalysts. They LOWER the activation energy and help SPEED UP biochemical reactions. Example: Carbonic Anhydrase

How do Enzymes Work?

What could affect Enzyme Activity? Substrate Concentration Activators/Inhibitors Coenzymes Temperature pH (Acidity/Basicity)