2. Enzymes

3. Chemical Reactions  Reactants  Products  Bonds are broken and reformed = new substances

4. 2 types of Chemical Reactions  Exothermic (Exergonic)  Releases Energy  Reactants have more energy than products  Ex:  Cellular Respiration

5. 2 types of Chemical Reactions  Endothermic (endergonic)  Absorbs Energy  Products have more energy than Reactants  Ex: Photosynthesis

6. How can you speed up chemical reactions?  Add Heat  Not so good for living organisms  Lower activation energy  How?  Use a catalyst  lowers activation energy  Ex:  Rolling rock over hill

7. How can you speed up chemical reactions?  Bull doze the top of hill  Lowers the activation energy

8.  Enzymes = Biological Catalyst  Protein that binds to reactants to make reaction happen easier/faster  No permanent change to enzyme; can be reused  Shape specific  Only work with specific molecules Enzymes

10.  Substrate  Reactants for a specific enzyme  Active site  Location on enzyme where substrate binds Substrates

13. Enzymes have optimal conditions  If conditions fall outside of optimal range enzymes denature (break down)  Change shape  Don’t work anymore

14. Metabolism  Biochemical Pathways  Series of enzyme controlled chemical reactions that transfer energy within the cell Enzyme 3 Enzyme 2 Enzyme 1 Enzyme 4 Reactant 1 Product 1 / Reactant 2 Product 2 / Reactant 3 Product 3 / Reactant 4 Final Product

15. Review Q’s  What type of organic macromolecule is an enzyme?  What’s a catalyst?  What does an enzyme do?  What do we call the reactants for a particular enzyme?  Where do the substrates bind to an enzyme?  Can one enzyme speed up all reactions? Why?  What is a Biochemical Pathway?