13. Metal ion catalysis is facilitated by any of several mechanisms, including
(A)electrophilic activity, which stabilizes negative charges on an intermediate.
(B) promoting formation of nucleophiles by affecting adjacent molecules.
(C) direct binding to substrate, increasing substrate-enzyme contacts.
(D) A and C.
(E) all of the above.

9. Two-dimensional electrophoresis is a combination of what two techniques? (A)isoelectric focusing and affinity chromatography (B) ion-exchange chromatography and SDS-PAGE (C) affinity chromatography and SDS-PAGE (D) isoelectric focusing and SDS-PAGE (E) isoelectric focusing and ion-exchange chromatography

10. The use of synthetic peptides includes (A)use as antigens for making antibodies (B) drugs (C) "hooks" used in purification (D) all of the above (E) A and C

11. Which of the following describes the Bohr effect? (A) Lowering the pH results in the release of O2 from oxyhemoglobin. (B) Increasing the pressure of CO2 results in the release of O2 from oxyhemoglobin. (C) Increasing the pH increases the T-form of hemoglobin. (D) All of the above. (E) A and B.

12. Which of the following is not correct concerning the oxygenation plot of proteins X and Y shown below? (A) Protein X exhibits tighter oxygen binding than protein Y. (B) Protein Y would function as a better transport protein than protein X. (C) Protein X exhibits cooperative binding, whereas Y does not. (D) Protein X corresponds to myoglobin, and protein Y corresponds to hemoglobin. (E) Protein Y contains multiple binding sites.

14. Restriction endonucleases cut DNA at specific sites. How many different patterns can be formed by a four-base sequence combination of any four bases? (A) 64 (B) 256 (C) 16 (D) 1024 (E) 4096

15. Hemoglobin-binding of oxygen is best described as a (A) concerted model. (B) Michaelis-Menten model. (C) sequential model. (D) combination of sequential and concerted models. (E) None of the above.

16. Which of the following is an epimer pair? (A)D-glucose and L-glucose (B) D-glucose and D-galactose (C) a-D-glucose and ẞ-D-glucose (D) D-glucose and D-fructose (E) D-mannose and D-galactose

17. Which of the following is not a reducing sugar? (A) glyceraldehyde (B) trehalose (C) cellobiose (D) maltose (E) fructose

18. Which of the following is not a heteropolysaccharide? (A)agarose (B) chitin (C) peptidoglycan (D) heparin (E) all of the above

19. Which of the following molecules or substances contain, or are derived from, fatty acids? (A)sphingolipids (B) prostaglandins (C) beeswax (D) all of the above (E) none of the above