Question

Amino acids generally exist in the form of Zwitter ions. This means they contain

• A. basic $—NH_{2}$ group and acidic $—COOH$ group
• B. the basic $—\overset{+}{N}H_{3}$ group and acidic $—COO^{-}$ group
• C. basic $—NH_{2}$ and acidic $—H^{+}$ group
• D. basic $—COO^{-}$ group and acidic $—\overset{+}{N}H_{3}$ group.

Answer 1

Answer: (D)

Zwitter ion contains both $+ve$ and $-ve$ charge. Proton of $—COOH$ group is transferred to the $— NH_{2}$ group. $—NH^{+}_{3 }$ group is acidic since it can donate a proton and $—COO^{-}$ group is basic since it can accept a proton.