1. Which amino acid is most likely to be positively charged at physiological pH? (A) Serine (B) Histidine (C) Glutamate (D) Tyrosine (E) Phenylalanine

2. Regarding Michaelis-Menten kinetics, which statement is correct? (A) Km equals substrate concentration at Vmax (B) Km is independent of enzyme concentration (C) Vmax increases linearly with substrate (D) Km applies only to allosteric enzymes (E) Vmax is determined solely by Km