1. METABOLISM ENERGY AND LIFE

2. METABOLISM The totality of an organisms chemical processes. CATABOLIC PATHWAYS Degradative Processes ANABOLIC PATHWAYS Building Processes

3. Complexity of Metabolism Bioenergetics – study of how organisms manage energy

4. THERMODYNAMICS 1 ST Law of Thermodynamics – Energy can be tranferred or transformed, but it can be neither created or destroyed. 2 nd Law of Thermodynamics – Every energy transfer or transformation increases the entropy (disorder or randomness) of the universe.

5. Organisms live at the expense of free energy

6. Chemical reactions may be classified based on free-energy changes. They are either –Exergonic – proceeds with a net release of free energy –Endergonic – absorbs free energy from its surroundings to proceed

7. ATP Powers Cellular Work A cell does three main kinds of work  Mechanical - beating of cilia, muscle contraction, chromosome movement  Transport – crossing a membrane against the concentration gradient  Chemical – building of polymers

8. What is ATP? The nitrogenous base adenine with a chain of three phosphates groups attached to the ribose.

9. When the terminal phosphate bond is broken, ATP becomes ADP. This is an exergonic reaction releasing 7.3kcal of energy per mole of ATP

10. The ATP Cycle

11. ENZYMES Catalytic proteins Substrate-specific Lock and Key fit Initiate chemical reactions without being used in the reaction ( reused) Named for their substrate usually and have the suffix (-ase)

12. The Catalytic Cycle of an Enzyme

13. Enzymes use a variety of mechanisms that lower activation energy and speed up a reaction. Enzymes allow reactions to take place at lower temperature ( body temperature).

14. Factors that affect enzyme activity Temperature –Up to a point, the velocity of the reaction increases with the increase in temperature –Most enzymes function optimally around body temperature (between 35 o -40 o C) –Above the optimal temperature, the hydrogen bonds of the enzyme disrupt and the enzyme is denatured pH –The optimal pH is between 6 and 8

15. Other Factors Affecting Enzyme Activity Cofactors – nonprotein helper –If it is organic, then it is a coenzyme –Most vitamins are coenzymes Enzyme inhibitors –Competitive site –Noncompetitive site