Amino acids usually exist in the form of Zwitter ions. This mean that they consist of

Options

A. basic-`NH_(2)` group and acidic -COOH group
B. the basic -`overset(+)(N)H_(3)` group and acidic `-C"OO"^(-)` group
C. basic `-NH_(2)` and acidic `-H^(+)` group
D. basic `-COO^(-)` group and acidic -`overset(+)(N)H_(3)` groups

Answer

D

Explanation

Zwitter ion contain 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.