1. Slides 1 to 74
Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings

2. Work, Energy and Reactions
Chapter 2
Work, Energy and Reactions

3. Chemical Reactions Metabolism All the chemical reactions in the body
Our cells capture, store and use energy to maintain homeostasis and support essential functions.
Reactants consumed
Products produced
Breaks or makes chemical bonds between atoms
Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings

4. Chemical Reactions
Work—movement or change in matter’s physical structure
E.g., running, synthesis
Energy—ability to do work
Kinetic energy
Potential energy
Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings

5. Chemical Reactions Basic Energy Concepts (continued)
Potential energy—stored energy
E.g., leopard lurks in a tree
Kinetic energy—energy of movement
E.g., leopard pounces on prey
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6. Chemical Reactions 3 types of reactions
Decomposition—breaks molecule into smaller pieces
Synthesis—assembles smaller pieces into larger one
Exchange/Replacement—shuffles pieces between molecules
Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings

7. Chemical Reactions Decomposition Reactions In chemical notation:
AB A + B
Releases covalent bond energy
Hydrolysis—Decomposition reaction with H•OH
E.g., food digestion
Catabolism—Sum of all the body’s decomposition reactions
Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings

9. Chemical Reactions Synthesis Reactions In chemical notation:
A + B AB
Absorbs energy
Formation of new bonds
Dehydration synthesis
Removal of H•OH between molecules
Anabolism—Sum of the body’s synthesis reactions
Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings

11. Chemical Reactions Exchange/Replacement Reaction In chemical notation:
AB + CD AC + BD
Decomposition and synthesis
Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings

12. Chemical Reactions Reversible Reactions A + B AB
Equilibrium—Condition when the forward and reverse reactions occur at the same rate
Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings

13. Chemical Reactions Key Note
When energy is exchanged, heat is produced. Heat raises local temperatures, but cells cannot capture it or use it to perform work.
Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings

14. Enzymes and Reactions Activation Energy
Quantity of energy needed to start a chemical reaction
Catalysts reduce activation energy to speed reaction
Enzymes catalyze cellular reactions
Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings

15. Enzymes and Activation Energy
Enzymes and Reactions
Enzymes and Activation Energy
Figure 2-7

16. Enzymes and Reactions Exergonic—Reactions that release energy
E.g., decomposition reactions
Endergonic—Reactions that consume energy
E.g., synthesis reactions
Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings