1. Essential Biochemistry by Pratt & Cornely, © 2004 John Wiley & Sons, Inc. Figure 15.01 Root nodules from clover.

2. Essential Biochemistry by Pratt & Cornely, © 2004 John Wiley & Sons, Inc. Figure 15.02 Model of the FeMo cofactor of nitrogenase.

3. Essential Biochemistry by Pratt & Cornely, © 2004 John Wiley & Sons, Inc. Figure 15.03 The nitrogen cycle.

4. Essential Biochemistry by Pratt & Cornely, © 2004 John Wiley & Sons, Inc. Figure 15.04 E. coli glutamine sythetase.

5. Essential Biochemistry by Pratt & Cornely, © 2004 John Wiley & Sons, Inc. Figure 15.05 PLP-catalyzed transamination.

6. Essential Biochemistry by Pratt & Cornely, © 2004 John Wiley & Sons, Inc. Figure 15.06 Nitrogen metabolism in context.

7. Essential Biochemistry by Pratt & Cornely, © 2004 John Wiley & Sons, Inc. Figure 15.07 Tetrahydrofolate.

8. γ-aminobutyrate Epinephrine Serotonin Melatonin

9. Essential Biochemistry by Pratt & Cornely, © 2004 John Wiley & Sons, Inc. Figure 15.12 The carbamoyl phosphate synthetase reaction.

10. Essential Biochemistry by Pratt & Cornely, © 2004 John Wiley & Sons, Inc. Figure 15.13 The four reactions of the urea cycle.

11. Essential Biochemistry by Pratt & Cornely, © 2004 John Wiley & Sons, Inc. Figure 15.14 The urea cycle and related reactions.

12. Essential Biochemistry by Pratt & Cornely, © 2004 John Wiley & Sons, Inc. Figure 15.15 Urease.