51. Which amino acid has the least polar R-group H? Glutamic Acid b. Leucine C. Serine d. Histidine e. Tyrosine Section: 2.1 52 Which amino acid would have the greatest negative charge at pH = 7.0? Tyrosine b. Histidine C: Leucine d. Serine Aspartic e. acid Section: 2.1