25. What effect would ketone bodies have on blood pH?
(A) Neutralize pH
(B) Lower pH
(D) Fluctuate pH
(E) No effect on pH
(C) Increase pH

21. Allopurinol is a drug used to treated chronic gout(痛風) because it inhibits_______.(A) ureate oxidase (B) adenosuccinase (C) adenosine deaminase (D) xanthine oxidase (E) guanine deaminase

22. Carbamoyl phosphate synthetase I deficiency is an autosomal recessive metabolic disorder that causes __________to accumulate in the blood. (A) bicarbonate (B) ammonium (C)ADP (D) phosphate (E) CO2

23. 5-Fluorouracil (5-FU) is used to treat cancers. It is a mechanism-based inhibitor of _________.(A) ribonucleotide reductase (B) thymidylate synthase (C) adenylosuccinate lyase (D) GMP synthetase (E) xanthine oxidase

24. Fatty-acid biosynthesis is vital in all biology. Which statement is correct? (A) The formation of malonyl-CoA requires micronutrient such as Mn2+. (B) The fatty-acid chain lengthening occurs either in ribosome or endoplasmic reticulum. (C) Double bonds can be introduced in Golgi body. (D) The carbon source at sites of endoplasmic reticulum is malonyl- ACP. (E) All of the above.

複選題26. The following figure shows the phi and psi angles of the residue X in a protein. (A) Phi angle is +45 degree. (B) Psi angle is –90 degree.(C) Phi angle is +90 degree.  (D) Psi angle is +60 degree. (E) Psi angle is +45 degree.

27. There are three proteins X, Y, and Z in 20 mM Tris (pH 7.0) solution. 1. Protein X is a homoheptamer. Its pI is 9.2. The molecular mass of each subunit of the protein X is 20,000 Da and the subunit's pl is 9.2.  2. Protein Y is a monomeric protein with molecular mass of 93,000 Da and its pl is 4.  3. Protein Z is a homodimer. Its molecular mass is 1 40,000 Da and its pI is 8. Please choose the correct answer? (A) When this mixture is loaded onto a cation exchange column, only protein Y can bind to the column: (B) When this mixture is loaded onto a size exclusion column, Protein Y is last eluted. (C) When this mixture is analyzed by a SDS- PAGE, the lowest band is protein Y. (D) When this mixture is analyzed by a SDS- PAGE, protein X and 'Z cannot be separated. (E) When this mixture is loaded onto a cation exchange column, protein X is the first eluted protein.

28. There are four peptides. Their sequences are: Peptide A : STRIKE Peptide B : ALLRIGHT Peptide C: CALENDAR Peptide D： HESSMAN The pI value of these four peptides should be (A) A＞B＞D＞C (B) C＞A＞B＞D (C) B＞A＞C>D (D) B＞A＞D＞C (E)A＞B＞C＞D

29. Because the enzymatic reaction rate is determined by the difference in energy between ES and_________ , the tighter binding of the substrate, the_________ the rate of reaction. (D) EXt; higher (A) S; higher (B) P; lower (C) EX+;lower (E) S; lower

30. In the enzyme catalyzed reaction sequence below, can the E- POA intermediate be predicted and why?(A) Yes, the mechanism is a double-displacement reaction. (B) No, the reaction is order single-displacement. (C) No, the reaction is double-displacement. (D) No, the reaction is random single-displacement. (E) None of the above. E:CrP -E + CiP

31. Which of the following statement regarding enzyme regulation is true? (A) Addition of an inhibitor to a V system results in kinetics similar to addition of a competitive inhibitor to a typical hyperbolic system. (B) Allosteric effectors are always more powerful than covalent modification. (C) Addition of an allosteric activator to a K system changes the plot of V vs. [S] from a sigmoidal curve to a more hyperbolic curve. (D) The T state of an enzyme generally has more activity than the R state. (E) None of the above is true.