1. a. Potential energy b. Kinetic energy Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. 1

2. AB Loss of electron (oxidation) AB A+A+ B–B– Gain of electron (reduction) e–e– + + lower energyhigher energy Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. 2

3. Disorder happens spontaneously Organization requires energy Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. 3

4. a. b. 0 0 Course of Reaction Products  G > 0  G < 0 Reactants Course of Reaction Products Free Energy (G) Energy Released Energy Supplied Free Energy (G) Energy Released Energy Supplied Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Energy is released Energy must be supplied 4

5. catalyzed 0 uncatalyzed Product Course of Reaction Reactant Free Energy (G) Energy Released Energy Suplied Activation energy Activation energy  G Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. 5

6. a. b. AMP CORE ADP ATP O ═ P — O O–O– — O O ═ P — O–O– O O ═ P — O–O– O — High-energy bonds Triphosphate group Ribose CH 2 H O HH H OH NH 2 C C N N N C N C CH H Adenine 6

7. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Energy from exergonic cellular reactions Energy for endergonic cellular processes PiPi ADP + H2OH2O ATP + 7

8. Active site a.b. EnzymeEnzyme–substrate complex Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Substrate 8

9. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. 1. The substrate, sucrose, consists of glucose and fructose bonded together. 2. The substrate binds to the active site of the enzyme, forming an enzyme– substrate complex. 3. The binding of the substrate and enzyme places stress on the glucose– fructose bond, and the bond breaks. 4. Products are released, and the enzyme is free to bind other substrates. Bond Glucose Fructose Active site Enzyme sucrase H2O 9

10. a. b. Rate of Reaction Optimum pH for pepsin Rate of Reaction pH of Reaction Optimum pH for trypsin 123456789 304050607080 Temperature of Reaction (C) Optimum temperature for human enzyme Optimum temperature for enzyme from hotsprings prokaryote Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. 10

11. a. Competitive inhibitionb. Noncompetitive inhibition Enzyme Allosteric site Active site Competitive inhibitor interferes with active site of enzyme so substrate cannot bind Allosteric inhibitor changes shape of enzyme so it cannot bind to substrate Active site Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Substrate Inhibitor 11

12. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Initial substrate Intermediate substrate A Intermediate substrate B Intermediate substrate C End product Enzyme1 Enzyme2 Enzyme3 Enzyme4 12

13. a.b. Enzyme 1 Enzyme 2 Enzyme 3 Enzyme 1 Enzyme 2 Enzyme 3 End product Initial substrate Intermediate substrate A Intermediate substrate B Initial substrate Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. 13