More Challenging Questions These questions require more thought and integrate several c...

More Challenging Questions

These questions require more thought and integrate several concepts.

The titration curves for the amino acids glutamic acid and lysine are given in the figure.

(a) Using the structural formulas given in Table 12.8, write the structural formulas for the forms of each amino acid

corresponding to points on the titration curve when 0, 1.0, 2.0, and 3.0 equivalents of OH- have been added. An equivalent in this case is the amount of base added that neutralizes an amount of H₃O⁺ ions equivalent to the amount of amino acid present.

(b) The isoelectric point is the pH at which an amino acid has no net charge. Write the structural formulas of glutamic acid and lysine at their isoelectric points.

(c) What relationship exists between the conjugate acid and conjugate base forms of these amino acids at each of the pK points noted on the titration curve?

Table 12.8