1. Chapter Twenty One Enzymes and Vitamins

2. Copyright © Houghton Mifflin Company. All rights reserved.21 | 2 Lipids cont’d © Mark E. Gibson / CORBIS ←CO 21.1

3. Copyright © Houghton Mifflin Company. All rights reserved.21 | 3 ←Fig. 21.1 Bread dough rises as a result of the action of yeast enzymes. Lipids cont’d Steven Needham / Envision

4. Copyright © Houghton Mifflin Company. All rights reserved.21 | 4 Table 21.1 Lipids cont’d

5. Copyright © Houghton Mifflin Company. All rights reserved.21 | 5 →Fig. 21.2 The active site of an enzyme is usually a crevice-like region formed as a result of the protein’s secondary and tertiary structural characteristics. Lipids cont’d

6. Copyright © Houghton Mifflin Company. All rights reserved.21 | 6 Fig. 21.3 The lock-and-key model for enzyme activity. Lipids cont’d

7. Copyright © Houghton Mifflin Company. All rights reserved.21 | 7 Fig. 21.4 The induced-fit model for enzyme activity. Lipids cont’d

8. Copyright © Houghton Mifflin Company. All rights reserved.21 | 8 ←Fig. 21.5 A schematic diagram representing amino acid R group interactions that bind a substrate to an enzyme active site. Lipids cont’d

9. Copyright © Houghton Mifflin Company. All rights reserved.21 | 9 →Fig. 21.6 A graph showing the effect of temperature on the rate of enzymatic reaction. Lipids cont’d

10. Copyright © Houghton Mifflin Company. All rights reserved.21 | 10 Lipids cont’d Meckles / Ottawa / Photo Researchers →CC 21.1

11. Copyright © Houghton Mifflin Company. All rights reserved.21 | 11 ←Fig. 21.7 A graph showing the effect of pH on the rate of enzymatic reaction. Lipids cont’d

12. Copyright © Houghton Mifflin Company. All rights reserved.21 | 12 Lipids cont’d © Leonard Lessin / Peter Arnold, Inc. →CC 21.2

13. Copyright © Houghton Mifflin Company. All rights reserved.21 | 13 →Table 21.2 Lipids cont’d

14. Copyright © Houghton Mifflin Company. All rights reserved.21 | 14 →Fig. 21.8 A graph showing the change in enzyme activity with a change in substrate concentration. Lipids cont’d

15. Copyright © Houghton Mifflin Company. All rights reserved.21 | 15 ←Fig. 21.9 A graph showing the change in reaction rate with a change in enzyme concentration for an enzymatic reaction. Lipids cont’d

16. Copyright © Houghton Mifflin Company. All rights reserved.21 | 16 Lipids cont’d  CAG 21.1

17. Copyright © Houghton Mifflin Company. All rights reserved.21 | 17 →Fig. 21.10 A comparison of an enzyme with a substance at its active site (a) and an enzyme with a competitive inhibitor at its active site (b). Lipids cont’d

18. Copyright © Houghton Mifflin Company. All rights reserved.21 | 18 ←Fig. 21.11 The difference between a reversible competitive inhibitor and a reversible noncompetitive inhibitor. Lipids cont’d

19. Copyright © Houghton Mifflin Company. All rights reserved.21 | 19 →Fig. 21.12 Conversion of zymogen to a proteolytic enzyme. Lipids cont’d

20. Copyright © Houghton Mifflin Company. All rights reserved.21 | 20 Lipids cont’d CAG 21.2

21. Copyright © Houghton Mifflin Company. All rights reserved.21 | 21 ←Fig. 21.13 Structures of selected sulfa drugs in use today as antibiotics. Lipids cont’d

22. Copyright © Houghton Mifflin Company. All rights reserved.21 | 22 →Fig. 21.14 Structures of selected penicillins in use today as antibiotics Lipids cont’d

23. Copyright © Houghton Mifflin Company. All rights reserved.21 | 23 Fig. 21.15 Selective binding of penicillin to the active site of transpeptidase. Lipids cont’d

24. Copyright © Houghton Mifflin Company. All rights reserved.21 | 24 →Table 21.3 Lipids cont’d

25. Copyright © Houghton Mifflin Company. All rights reserved.21 | 25 →CC 21.3 Lipids cont’d

26. Copyright © Houghton Mifflin Company. All rights reserved.21 | 26 →Table 21.4 Lipids cont’d

27. Copyright © Houghton Mifflin Company. All rights reserved.21 | 27 →Fig. 21.16 Drawing of a blood sample. Lipids cont’d Saturn Stills / SPL / Photo Researchers

28. Copyright © Houghton Mifflin Company. All rights reserved.21 | 28 ←Fig. 21.17 Rows of cabbage plants. Lipids cont’d © Jeff Greenberg / Peter Arnold, Inc.

29. Copyright © Houghton Mifflin Company. All rights reserved.21 | 29 →Fig. 21.18 The quantity of vitamin D synthesized by exposure of the skin to sunlight varies with latitude, exposure time, and skin pigmentation. Lipids cont’d Melissa Grimes-Guy / Photo Researchers

30. Copyright © Houghton Mifflin Company. All rights reserved.21 | 30 →Table 21.5 Lipids cont’d

31. Copyright © Houghton Mifflin Company. All rights reserved.21 | 31 →Table 21.6 Lipids cont’d

32. Copyright © Houghton Mifflin Company. All rights reserved.21 | 32 →Table 21.7 Lipids cont’d