Question

Amino acid generally exists in the form of Zwitter ions. This means they contains

• A. Basic $- \mathrm { NH } _ { 2 }$ group and acidic – COOH group
• B. The basic $- \stackrel { + } { \mathrm { N } } \mathrm { H } _ { 3 }$ group and acidic $- \mathrm { COO } ^ { - }$Group
• C. Basic $- \mathrm { NH } _ { 2 }$ and acidic $- \mathrm { H } ^ { + }$ group
• D. Basic $- \mathrm { COO } ^ { - }$ group and acidic $- \stackrel { + } { \mathrm { N } } \mathrm { H } _ { 3 }$group.

Answer 1

Answer: (D)

Basic $- \mathrm { COO } ^ { - }$ group and acidic $- \stackrel { + } { \mathrm { N } } \mathrm { H } _ { 3 }$group.

Answer 2

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