4. The catalytic mechanism below is an example of:

(A) covalent nucleophilic catalysis.
(B) covalent electrophilic catalysis.
(C) specific base catalysis.
(D) general base catalysis.
(E) general acid catalysis.

1300管徑50㎜以下者，配至機器設備或油(水)箱(櫃)時，或與使用螺紋街口之閥等連接，或日後須拆卸保養之處，均應使用(A)管套節 (B)彎頭 (C)三通 (D)大小頭。

1. Which description is   correct  ? (A) Mannose is a C4 epimer of glucose. (B) D-glucose and D-glucuronic acid is different on C6. (C) Dextran is obtained from algae. (D) Hyaluronan is sulfated hetereopolysaccharide. (E) α-Keratin is a protein which provides strength in connective tissue.

2. Which description is   correct  ? (A) Every turn of α-helix is 3.6 Å in length. (B) Amyloid is homopolysaccharide and composed of glucose linked by the α1→4 linkage. (C) Interconversion between α-D-Glc and β-D-Glc is called mutarotation. (D) Aldohexose has eight stereoisomers. (E) Glc-β1,4-Glc could be drawn as the structure below. CH2OH O | OH | CH2OH O | OH \ O / \ OH OH | OH

3. In the catalytic triad of chymotrypsin protease, _____ increases the basicity of _____thus allowing deprotonation of _____ to serve as a nucleophile. (A) Ser, His, Asp (B) His, Ser, Asp (C) Ser, His, His (D) Asp, His, Ser (E) Cys, His, Ser

5. Which statement below about contrasting Hb and Mb is   false  ? (A) Hb shows sigmoidal, whereas Mb shows hyperbolic oxygen saturation curves. (B) Hb shows cooperativity, whereas Mb does not. (C) Hb binds O2 more tightly than Mb. (D) Oxygen binds to a ferrous ion in both proteins. (E) Hb-oxygen binding is dependent on physiological changes in pH, whereas Mb-oxygen binding is not.

6. Which of the following statements regarding enzyme regulation is   true  ? (A) The conversion of trypsinogen to trypsin is an example of zymogen activation. (B) Allosteric effectors are always more powerful than covalent modification. (C) Addition of an inhibitor to a reaction system results in kinetics similar to addition of a competitive inhibitor to a typical hyperbolic system. (D) The T state of an enzyme generally has more activity than the R state. (E) All are true.

7. Which statement regarding glycogen and its metabolism is   correct  ? 　 1. Highly branched glycogen is less soluble than unbranched glycogen. 　 2. Having more ends effectively increases the rate of glycogen synthesis and breakdown. 　 3. To enter glycolysis, glucose-1-phosphate must undergo isomerization to glucose-6-phosphate by phosphoglucomutase. 　 4. To replenish glucose in the bloodstream, glucose-1-phosphate must be hydrolyzed to free glucose by glucose-1-phosphatase. (A) 1, 2, and 3 are correct. (B) 2, 3, and 4 are correct. (C) 1, 2, and 4 are correct. (D) All are correct. (E) None is correct.

8. The metabolic function of the pentose phosphate pathway is to? (A) act as a source of ADP biosynthesis. (B) participate in oxidation-reduction reactions during the formation of H2O. (C) provide intermediates for the citric acid cycle. (D) generate NADPH and pentoses for the biosynthesis of fatty acids and nucleic acids. (E) synthesize phosphorus pentoxide.

9. Which one has ether bond rather than ester bond? (A) Phosphotidylcholine (B) Phosphotidylserine (C) Plasmalogen (D) Phosphotidylethanolamine (E) Sphingomyosin

10. Which one is the basic unit for the synthesis of cholesterol? (A) Malonyl-CoA (B) Serine (C) Palmitoyl-coA (D) Isoprene (E) L-glycerol 3-phosphate