TWO PROBLEMS (30%)
1) You are given EIGHT molecules as follows:
i. Pro-Gln-Gly-Met-Asn-Met-Phe-Pro
ii. Glu-Asp-Gly
iii. Ala-Leu-Lys-Gln-Asn
iv. ATGC
v. Gln-His-Arg-Gly
vi. Phe-Trp-Gly-Leu-Glu-Asn-Cys
vii. Val-Arg-Ala-Asp-Asn-Met-Glu-Ile
viii.
(n = 30)
1. Please predict the charges of the following EIGHT molecules as shown above under i) pH 1, ii) pH 7 and iii) pH 13.
2. You carried two-dimensional electrophoresis (first dimensional is done by isoelectric focusing, the 2nd dimension is done by SDS- PAGE) with the EIGHT molecules as mentioned above, please predict results at the end of two-dimensional electrophoresis. Please explain your predicted results based on the properties of the molecules.
3. Please draw the structure of Ala-Leu-Lys-Gln-IIe, by keeping the nature of peptide bond in mind.
[60 points]
2) The question concerns the buffering effect of acid/base system.
1. i) What is the pH of a solution of that contains 0.15 M Na+H2PO4- and 0.65 M (Na+)2HPO42-?
2. ii) What would the concentration of Na+H2PO4- be at pH 6 if 0.15M (Na+)2HPO42- was adjusted to that pH.
3. iii) What would be the concentration of Na+H2PO4- be at pH 3 if the solution in ii was adjusted to that pH. Please provide the rationale behind this calculation.
[40 points]