2. Enzymes Special proteins Increase the speed of biochemical reactions (catalysts) Lower the activation energy of chemical reactions Usually end in “ ase ” Named after the substrate they act upon Critical to life

3. How Enzymes Work Active site: region where the reaction takes place – specific shape Substrates: reactants – specific shape – bind to active site

4. How Enzymes Work 1.Substrates bind to enzyme ’ s active site. - lock and key or puzzle piece fit

5. How Enzymes Work 2. Enzyme substrate complex - chemical reaction occurs Enzyme-Substrate Complex

6. How Enzymes Work 3. New products are released - enzyme can be used again

7. Types of Reactions Decomposition: when a large molecule is broken down into smaller molecules – Ex: 2H 2 O 2  2H 2 O + O 2 Enzyme = catalase Synthesis: when 2 or more small molecules are combined to form a larger molecule – Ex: RNA Polymerase combines nucleotides to form RNA

8. How Enzymes Work http://highered.mcgraw- hill.com/sites/0072495855/student_view0/chapter2/animation_ _how_enzymes_work.html

9. Conditions Most enzymes need a certain temperature and pH range If enzymes are exposed to conditions outside their designated temperature and pH range, they could denature (unfold and become non-functional) http://www.youtube.com/watch?v=SUCgAxI8rhg

10. Quiz Substrates/Reactants Active Site Enzyme Enzyme-Substrate Complex Product

11. Quiz (cont.) Decomposition or Synthesis Reaction?