1. Chemical Reactions and Enzymes

2. What is a Chemical Reaction? • A process occurs when molecules interact to produce new chemical compounds • Examples: CH4 + 2O2  CO2 + 2H2O 2HCl + CaCO3  CaCl2 + CO2 + H2O

3. Sign of Chemical Reactions • Gas formed • Precipitate (solid from solutions) formed • Color change • Temperature change • Odor produced

4. Chemical Reactions and Energy • Energy is required to break chemical bonds • Energy is released when new bonds form • Some reactions are spontaneous • Many reactions require some energy input to get started

5. Catalysts • Catalysts are substances that speed up a reaction without being used up in the reaction • They act by reducing the energy needed to start the reaction

6. Factors Affecting Chemical Reactions • Temperature • Concentration of reactants • Presence of catalyst • Surface area exposed on solid reactants

7. Enzymes • Enzymes are proteins that act as catalysts • Many enzymes are involved the processes of photosynthesis, cellular respiration, and fermentation

8. http://www.chem4kids.com/files/bio_enzymes.html

9. http://www.chem4kids.com/files/bio_enzymes.html

10. Factors Affecting Enzymes • pH • Temperature • Concentration of substrate • Inhibitory molecules • Activator molecules • pH or temperature can denature or change the shape of the enzyme so it no longer fits the substrate