Which of the following is true of the isoelectric point of amino acids?
A) The isoelectric points of all amino acids are the same.
B) It is the pH at which an amino acid conducts electricity.
C) It is the pH at which an amino acid has equal numbers of positive and negative charges.
D) All of the above are true.

Question

Quizplus · Accepted Answer

The isoelectric point (pI) of an amino acid is the pH at which the molecule carries no net electrical charge. This means that the number of positive charges (from amino group, NH3+) is equal to the number of negative charges (from carboxyl group, COO-). The pI is not the same for all amino acids and it is not related to the ability to conduct electricity.

Which of the Following Is True of the Isoelectric Point