1. Chemical Reactions And Enzymes

2. Chemical Reactions  Processes that change one set of chemicals into another set of chemicals Reactants  Products (bonds break) (new bonds form)

3. Energy in Reactions  Some reactions release energy -often spontaneously  Some reactions absorb energy -need an energy source What significance do these energy changes have for living things?

4. Activation Energy  The energy needed to start a reaction

5. Enzymes  Some reactions are too slow or have activation energies that are too high  Catalyst – a substance that speeds up the rate of a chemical reaction

6. Enzymes (cont.)  ENZYMES (proteins) act as biological catalysts  They speed up chem.rxns. inside cells  Lower the activation energy  They are very specific (catalyze 1 reaction)  See pg. 51, Figure 2-20

7. CO 2 + H 2 O  H 2 CO 3

8. Enzyme Action  Reactants need enough energy for bonds to break  Enzymes provide a site where reactants can be brought together to react (active site)  The site reduces the energy needed  Substrates -the reactants of enzyme-catalyzed reactions (ex. Hexokinase, pg. 52-53) Substrates

9. Enzyme-Substrate complex

11. Enzyme Activity  Enzymes can be affected by any variable that influences a chemical reaction. Denatured  examples: pH, temperature change  Enzymes in human cells work best at 37°C (normal body temp.)  Lew-port enzymesLew-port

12.  Cells have proteins that help turn enzymes on and off  Enzymes are important in: -regulating chemical pathways -making materials that cells need -releasing energy -transferring information -form tissues -fight disease

13. Hydrolysis of Gelatin  Proteases-enzymes that break down other proteins into smaller polypeptides, amino acids  Isolated from strains of Bacillus bacteria -stable at High Temp -can be genetically engineered

15.  Stable at alkaline pH, various temps.  Added to laundry detergents  Can be genetically engineered

16. http://http://homepage.smc.edu/wissmann_paul/anatomy2t extbook/AAcidsProteins.htmlhomepage.smc.edu/wissmann_ paul/anatomy2textbook/AAcidsProteins.htmlhttp://homepage.smc.edu/wissmann_paul/anatomy2t extbook/AAcidsProteins.html