1. Thermodynamics and Metabolism

2.  Metabolism = Catabolism + Anabolism  Catabolic reactions are energy yielding breakdown of more-complex molecules into simpler ones  Anabolic reactions are energy requiring building up of simpler molecules into more- complex ones Metabolism

4. 1 st : “Energy can be transferred or transformed but neither created nor destroyed.” 2 nd : “Every energy transfer or transformation increases the disorder (entropy) of the universe.” Note especially the waste heat First and Second Laws of Thermodynamics

5.  Organisms take in energy & transduce it to new forms (1st law)  As energy transducers, organisms are less than 100% efficient (2nd law) Energy in the Biosphere

6. Organisms employ this energy to:   Grow   Protect Themselves   Repair Themselves   Compete with other Organisms   Make new Organisms (i.e., babies)

7.   In the process, organisms generate waste chemicals & heat   Organisms create local regions of order at the expense of the total energy found in the Universe!!! We are Energy Parasites!

8. Kinetic and Potential Energy

9.  First Law of Thermodynamics: Energy can be neither created nor destroyed Therefore, energy “generated” in any system is energy that has been transformed from one state to another (e.g., chemically stored energy transformed to heat)

10.   Second Law of Thermodynamics:   Efficiencies of energy transformation never equal 100%   Conversion to heat is the ultimate fate of chemical energy

11. Downhill Increase stability Greater entropy  G < 0

12. Potential energy Work Spontaneous“Food” Forward reaction Waste heat

13. Types of Reactions

14. Energy released “Food” Movement toward equilibrium 1. Exergonic Reactions

15. Decrease in Gibbs free energy (-  G) Increase in stability Spontaneous (gives off net energy upon going forward) Downhill (toward center of gravity well, e.g., of Earth) Movement towards equilibrium Coupled to ATP production (ADP phosphorylation) Catabolism

16. Energy required “Work” 2. Endergonic reactions

17. Decrease in stability Not Spontaneous (requires net input of energy to go forward) Movement away from equilibrium Coupled to ATP utilization (ATP dephosphorylation) Anabolism

19. Coupling Reactions Exergonic reactions can supply energy for endergonic reactions

20. Energy Coupling in Metabolism Catabolic reaction Anabolic reaction Catabolic reactions provide the energy that drives anabolic reactions forward

21. Adenosine Triphosphate (ATP)

22. Energy Coupling via ATP

23. Hydrolysis of ATP

24. Various Pi Transfers

25. Summary of Metabolic Coupling Endergonic reaction Exergonic reaction Endergonic reaction Exergonic processes drive Endergonic processes

26. Electron Carriers  Compounds that pick up electrons from energy- rich compounds and donate them to low-energy compounds  Redox reaction: LEO the lion says GER

27.  Electrons that pass from one to another carry energy with them, so the reduced form of a molecule is always at a higher energy level than the oxidized form

28. Anabolic process Catabolic process Chemically stored energy

30. The End