Isoelectric point of an amino acid is the pH at which the amino acid molecules

The isoelectric point(pl) of an amino acid is the pH of wihc it has no net charge. The pl of an amino acid that does not have an ionizable side chain such as alanine, is midway between its two pka values. If an amino acid has ionizable side chain. its pl is the average of the pka values of the similarly ionizing groups. Find the structure of the following amino acids at pH=1:

Isoelectric Point OF Amino Acid

At isoelectric point, amino acid is present as

At isoelectric point, amino acid is present as

Explain isoelectric point of alpha -amino acids.

What is isoelectric point amino acid ? How does it help in the sepration of amino acids ?