7. Consider the figure below. HO -C pka-COOH-2.19 pka-NH2 = 9.67 pka-sidechain 4.25 CHCH2C OH a. What amino acid is this? (1) b. Is it in the R or S configuration? (2) c. Draw the three forms of the amino acid (3) d. Calculate the pl of the amino acid and explain at what pH values it would act as a good buffer. (4) e. If an aqueous solution of this amino acid is buffered at a pH of 4.45 and 0.1 M of the acid is added, what would the change in pH be? (4)