Question

An aminoacid under certain conditions have both positive and negative charges simultaneously in the same molecule. Such a form of aminoacid is called ______.

Options

• Acidic form

• Basic form

• Aromatic form

• Zwitterionic form

Answer 1

An aminoacid under certain conditions have both positive and negative charges simultaneously in the same molecule. Such a form of aminoacid is called zwitterionic form.

Explanation:

In an aqueous solution, the carboxyl group can lose a proton and the amino group can accept a proton, giving rise to a dipolar ion called the Zwitter ion. Zwitter ion is neutral but contains both positive and negative charges.

\[\begin{array}{cc}
\phantom{....}\ce{R}\phantom{.........................}\ce{R}\phantom{........................}\ce{R}\phantom{.......}\\
\phantom{...}|\phantom{..........................}|\phantom{.........................}|\phantom{......}\\
\ce{H3N^+ - \underset{(A)}{CH} - COOH ⇌ H3N^+ - \underset{\underset{Zwitter ion}{(B)}}{CH} - COO^-  ⇌ H2N - \underset{(C)}{CH} - COO^-}\\
\end{array}\]