So 4.1 plus 3.1, that gives us 7.2. We divide that by two, that gives us 3.6. So what that means is at a PH of 3.6, these two negative charges from these two groups will exactly cancel out this positive charge found on this terminal alpha amino group. And so at this particular PH value, this will have a net charge of zero. Now let's move on to case number three. Let's suppose we have an ionizable amino acid, but it is basic.