At physiological pH, which of these amino acids has a positive charge?
(A) Valine (B) Aspaic acid (C) Arginine (D) Isoleucine
(C) Ans: C. ArginineAt physiological pH, arginine has a positive charge.Negative Charged (Acidic Side Chains) - Aspaic acid & glutamic acid.Positive Charged (Basic Side Chains) - Histidine, arginine & lysine.