1. Metabolism The total of all reactions in a cell

2. Components of Metabolism Catabolism Breakdown of large molecules into smaller ones Energy is released

3. Components of Metabolism Anabolism Building of large molecules from smaller ones Energy is required

4. Energy Basics Two types—kinetic & potential Many forms—chemical, electromagnetic, mechanical, heat, nuclear Energy can be transformed from one type to another

5. 1 st Law of Thermodynamics Energy can be neither created nor destroyed but it can change forms Energy is conserved in a reaction

6. 2 nd Law of Thermodynamics Every energy transfer or transformation makes the universe more disordered. Entropy—The measure of the amount of disorder or randomness

7. Which has more entropy??? A cluttered closet or a well- organized closet? An ice cube or a glass or water? A gallon of gasoline or the carbon dioxide and water vapor that escape the exhaust pipe?

8. There is an unstoppable trend toward randomization in nature Heat is a very disorganized form of energy and is the fate of all energy transformations. The quantity of energy in the universe is constant, but its quality is not.

9. Reactions that occur spontaneously Increase the stability of the system Increase the entropy (randomness or disorder) of the system

11. Spontaneous reactions Release energy that can perform work This energy is known as free energy It is represented by the letter G

12. Free energy is A measure of a system’s instability Systems that change to a more stable state have high free energy, low entropy or both.

13. The ATP molecule ATP is the energy currency for cellular work. Cells do the following kinds of work: Mechanical work Transport work Chemical work

15. The ATP molecule Is highly organized (low entropy) Very unstable (negative phosphates in close proximity) Therefore, has a very high free energy ΔG = -7.3 kcal/mol for hydrolysis of ATP

16. Free Energy and Equilibrium Equilibrium is point of maximum stability At equilibrium ΔG = 0, there is no change in the system At equilibrium, cells are dead! Cells must remain at disequilibrium to continue to work

18. Exergonic reactions Release free energy ΔG is negative Occur spontaneously Can do work Respiration is an example ΔG for respiration = -686 kcal/mol

19. Endergonic Reactions Absorbs free energy ΔG is positive Do not occur spontaneously Photosynthesis is an example ΔG for photosynthesis is 686 kcal/mol

21. Analyze the ATP Cycle in terms of anabolism, catabolism, endergoonic, exergonic, and free energy

24. How does ATP work?