5. In the catalytic triad common to many serine proteases, _ increases the basicity of _____ thus allowing deprotonation of _____ to serve as a nucleophile.
(A) Ser, His, Asp.
(B) Asp, His, Ser.
(C) Ser, His, His.
(D) His, Ser, Asp.
(E) Cys, His, Ser.

1. Which of the following pairs of bonds can rotate within a peptide backbone and the torsion angle of the latter is assigned as psi angle? (A)(B)(C)(D)(E)

2. Which of the following statements is   false  ? (A) One protein has one conformation but has many configurations. (B) An α-helix can be destabilized by the presence of two Lys residues near the amino terminus of the α-helix. (C) Determining the precise spacing of atoms within a large protein is possible only through the use of x-ray diffraction. (D) Protein domains may retain their correct shape even when separated from the rest of the protein. (E) Proteins are classified within families or superfamilies based on similarities in structure and/or function.

3. RecA enzyme requires for catalysis. When the enzyme lacks , it would be referred to as the: (A) apoenzyme. (B) substrate. (C) coenzyme. (D) holoenzyme. (E) prosthetic group.

4. Catalytic antibodies, also called _____ are generated against an antigen that is: (A) zymogens； an analog of the product of the reaction. (B) abzymes； the substrate of the reaction. (C) abzymes； an analog of the transition-state intermediate in the reaction. (D) zymogens； an analog of the transition-state intermediate in the reaction. (E) holoenzyme； the substrate of the reaction.

6. Negative cooperativity of Rep helicase from E. coli means that: (A) once it binds ssDNA, binding dsDNA is prohibited. (B) when both subunits are bound to DNA, ATP hydrolysis promotes release of both subunits. (C) ATP hydrolysis promotes DNA binding of both subunits simultaneously. (D) when one subunit binds DNA, the other releases from the DNA. (E) when one subunit binds DNA, the other binds tightly to the DNA.

7. Each of the following vitamins is required for reactions in the oxidation of pyruvate to CO2 and H2O   except  ? (A) biotin. (B) pantothenate. (C) niacin. (D) thiamine. (E) riboflavin.

8. Which one of the following statements concerning biotin and gluconeogenesis is   not true  ? (A) Biotin is used to add CO2 to certain intermediates in gluconeogenesis. (B) CO2 is incorporated into the glucose product. (C) Biotin is capable of binding covalently to CO2. (D) Biotin helps synthesize an important precursor of phosphoenolpyruvate. (E) ATP hydrolysis is required to attach CO2 to biotin.

複選題9. Which of the following statements is   true  ? (A) One of the reason why the enzyme catalyzes the synthesis of citrate is called citrate synthase is because the reaction requires ATP. (B) Pyruvate dehydrogenase, isocitrate dehydrogenase, and succinyl-CoA synthase catalyze reactions that release CO2. (C) Aconitase catalyzes reaction that transforms from an achiral to chiral molecule. (D) Reactions catalyzed by succinate dehydrogenase releases GTP. (E) Animals can use fat or acetate as the carbon source because they can replenish TCA cycle intermediates by anaplerotic reaction.

10. Which one is   not   a component of the plasma membrane? (A) Sphingolipid. (B) Phosphatidylcholine. (C) Triacylglycerol. (D) Sterol. (E) Glycolipids.

11. Which modification is   not   required for lipid anchor proteins? (A) Myristoyl. (B) Palmitoyl. (C) Prenyl. (D) Glycosyl phosphatidylinositol. (E) Phorphorylation.