Charged Molecules of Life

Amino acids and pH

An interactive lesson with 4 steps, about 5 minutes: you predict, drag and solve, with instant feedback on every answer. It runs in your browser and needs JavaScript.

What you’ll learn

• Each acidic group is protonated below its pKa and deprotonated above.
• Amino acids are zwitterions near neutral pH; pI = average of the two pKa values.

Steps

1. Two groups, two pKa values
2. No net charge
3. Sorting proteins
4. Fraction charged