1. Enzymes

2. Chemical Reactions Energy breaks chemical bonds
Energy released (heat & light)
Energy stored in new bonds
Activation Energy: amount of energy needed to start a reaction

3. Exothermic Reactions Exo = exit; thermic = heat
Defined: Release more energy than it absorbs
Light & heat
Ex: Cellular Respiration
Process that creates energy for cells
Chemical energy released for cells…
Heat energy released for warmth

4. Endothermic Reactions
Endo = within; thermic heat
Defined: Absorb more energy than it releases
Ex: Photosynthesis
Sunlight has more energy than sugar produced

5. Enzymes Activation energy usually comes from an increase in temp
Slow process
Catalyst: substance that decreases the activation energy needed to start a chemical reaction
Speeds up reaction
Enzymes reduce energy needed (activation energy) to start a chemical reaction

6. Controlled Settings Human body ~98.6°F
Can’t raise body temp to start reactions.
Internal reactions would be too slow to sustain life without a catalyst
Ex: Saliva
Breaks down starch 1,000,000x faster with amylase

7. Enzyme Structure
Enzyme shape allows specific reactants to bind together
Reactants = substrate
Ex: Amylase & starch: Starch is the substrate because it binds to amylase
Substrates binds to activation sites on the enzyme (key fitting into a lock)
Once binded to enzyme, substrates bonds weakened
Substrates bonds break
Substrates re-bond to each other