Thie presentation focuses on major biological concepts from Chapter 2 of BSCB Blue: A Molecular Approach

1. Energy and Organisms

3. Chemical Reactions Make Life Possible! Autotrophs Heterotrophs and Autotrophs Photosynthesis Cellular Respiration

7. Chemical Reactions Proceed as Follows: Reactants Products Metabolism and Energy Transfer Energy must be added to “ activate ” the reaction and break the bonds between atoms

8. Under Normal Conditions, a High Amount of Energy is Needed to Start a Reaction Activation Energy In cases like this ( High AE ), reactions would occur too slowly to support life!!! Energy of Reactants Energy of Products

9. Catalysts Catalysts speed up the rate of a reaction by lowering the activation energy needed to get the reaction going Catalysts are not changed or used up during a reaction!

10. A Catalyzed Reaction… Requires less energy to get started!!! Energy of Reactants Energy of Products Activation Energy

12. How do Enzymes Work? Bind to Specific Reactants to Form a Complex Reactants called Substrates Substrate Binds to the Enzyme at the Active Site

13. Enzymatic Reactions Important Enzyme: Catalase Breaks H 2 O 2 into H 2 O and O 2 Hydrogen Peroxide is Toxic to Cells Enzymes use “induced fit” to help bonds form or break between compounds E + S ES E + P Catalase + H 2 O 2 Complex Catalase + H 2 O + O 2

16. Chemical Reactions in Organisms Metabolism : All the chemical activities in a cell or organism Synthesis: “building-up” reactions biosynthesis, photosynthesis dehydration synthesis Decomposition: “breaking down” reactions cellular respiration, digestion hydrolysis