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Three facts solve all electrophoresis problems: (1) At pI, amino acid has zero net charge → no migration. (2) At pH < pI, net positive charge → migrates to cathode (negative electrode). (3) At pH > pI, net negative charge → migrates to anode (positive electrode). Calculating pI: Neutral amino acids (Gly, Ala, Val, Leu): pI = (pKa1 + pKa2)/2 ≈ (2.3 + 9.7)/2 ≈ 6.0. Acidic amino acids (Asp, Glu): pI = (pKa1 + pKaR)/2 ≈ (2.0 + 3.9)/2 ≈ 3.0 (use the TWO acidic pKa values). Basic amino acids (Lys, Arg): pI = (pKa2 + pKaR)/2 ≈ (9.0 + 10.5)/2 ≈ 9.7 (use the TWO basic pKa values). At pH 7: acidic amino acids (pI ~3) are above pI → anion → anode. Basic amino acids (pI ~10) are below pI → cation → cathode. Neutral amino acids (pI ~6) are near neutral → slight negative charge → slow migration to anode. This framework handles any JEE electrophoresis question in under 30 seconds.