How does the ionizable nature of -NH2 and -COOH groups effect the structure of the amino acid? Please explain with an example.

Dear student.

An amino acid has a basic amine group and an acidic carboxylic acid group. This structure internally transfers a hydrogen ion from COOH group to amine group leaving positive and negative charges on both. Such a structure is called a zwitterion.

At low pH: It means the medium is acidic i.e., there are enough H+ ions in medium so that the the carboxylate group tends to accept proton and form
 


At high pH: It means the medium is basic i.e., there is low concentration of H+ ions and high concentration of OH- ions so that the NH3 + of zwitter ion  loss a proton  to form NH2
 



At neutral pH the amino acid tend to form Zwitter ion.
 



Regards.

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