Growth factor Analog NH2 NH2 CH2-C-COOH CHz-C-COOH Amino Acid H H Analogs Phenylalanine (an amino acid) p-Fluorophenylalanine HN HN Nucleic Acid H H Analogs Uracil 5-Fluorouracil (an RNA base) (a uracil analog) CH3 HN HN Thymine 5-Bromouracil (a DNA base) (a thymine analog) Figure 20-18 Brock Biology of Microorganisms 11/e 2006 Pearson Prentice Hall,Inc.Nucleic Acid Analogs Amino Acid Analogs