Why is the isoelectric point (pI) significant in isoelectric focusing?

How is a stable pH gradient established in an isoelectric focusing gel?

How does the relationship between pH and pI affect protein migration in an electric field during isoelectric focusing?

What is the process by which proteins stop migrating in an isoelectric focusing gel?

If a protein with a pI of 9.0 is placed in a gel with a pH gradient from 3 to 10, what will be its behavior?

If a protein stops migrating at a pH of 4.5 in an isoelectric focusing gel, what is its isoelectric point?

Which of the following is NOT a practical application of isoelectric focusing?