1. Metabolism
Energy of Life

2. Metabolic Pathways
Anabolic Pathways Catabolic Pathways

3. Kinetic Energy

4. Potential Energy

5. First Law of Thermodynamics
Energy can be transferred or transformed but it cannot be created or destroyed

6. Second Law of Thermodynamics
Every energy transfer or transformation increases the entropy of the Universe

7. Free Energy Gibbs Equation DG = DH – TDS DG – Change in Free energy
DH – Change in Total energy
T – Absolute temperature in Kelvin
DS – Change in Entropy

8. Free Energy and Metabolism

9. Free Energy and Metabolism
Exergonic Reactions
Release of energy
-DG
Spontaneous
Downhill
More energy in reactants than in products
Ex. Cellular Respiration
-686 kcal/mol
Ex. ATP  ADP + P
-7.3 kcal/mol
Endergonic Reactions
Absorbs energy
+DG
Nonspontaneous
Uphill
More energy in products than in reactants
Ex. Photosynthesis
+686 kcal/mol
Ex. ADP + P  ATP
+7.3 kcal/mol

12. Enzymes Biological Catalyst
Speed up metabolic reactions by lowering the energy of activation

14. Enzymes
Substrate Specific
Active Site
Induced Fit
Recycled

15. Enzymes
Inhibitors
Competitive
Noncompetitive

16. Enzymes
Allosteric Sites
Cooperativity

17. Feedback Inhibition
Pathway switched off