27. Gout is caused by aberrant degradation of purine, leading to accumulation of uric acid. Allopurinol inhibits_______, leading to reduce the production of uric acid.
(A) purine nucleoside phosphorylase
(B) xanthine oxidase
(C) nucleotidase
(D) urease
(E) hypoxanthine-guanine phosphoribosyltransferasse

23. Which of the following amino acids is the crucial precursor for the biosynthesis of melatonin? (A) Phenylalanine(B) Methionine(C) Lysine(D) Tryptophan

24. Which is not an electron acceptor in the mitochondrial respiratory chain? (A) FMN(B) FAD(C) Fe3+(D) Cu2+ (E) Coenzyme A

25. Which is the active sugar in glycogen synthesis in animal? (A) CDP-glucose (B) GDP-glucose (C) UDP-glucose (D) Glucose 6-phosphate (E) Glucose 1-phosphate

26. Which of the following compounds is not a product of the enzymatic steps in the citric acid cycle? (A) Acetyl-CoA (B) -ketoglutarate (C) Succinate (D) Fumarate (E) Malate

28. Which of the following enzymes cannot catalyze the formation of a phosphodiester bond? (A) RNA polymerase (B) DNA polymerase (C) Ligase (D) Endonuclease (E) Reverse transcriptase

複選題29. Histones are found in eukaryotic cell nuclei that package and order the DNA into structural units called nucleosomes. They are usually rich in _______, and they interact with DNA via _______. (A) lysine and arginine; ionic bonds (B) glutamic acid and aspartic acid; hydrogen bonds (C) alanine and glycine; ionic bonds (D) lysine and arginine; hydrogen bonds (E) glutamic acid and aspartic acid; ionic bonds

30. The binding of _______ with lac repressor can activate the transcription of lac operon. (A) arabinose (B) isopropyl β-thiogalactoside (C) tryptophan (D) β-galactosidase (E) mannose

61. A mixture of four amino acids is separated by using a cation exchanger with an elution gradient of increasing NaCl solution. What is the correct elution sequence? (A) Asp, Lys, Arg, Ser(B) Asp, Ser, Lys, Arg(C) Asp, Arg, Ser, Lys (D) Ser, Asp, Arg, Lys(E) Lys, Arg, Ser, Asp

62. For an α-has the sequence : +H3N-Asp-Trp-Gln-Leu-His-Val-Phe-Ala-Lys-Val-Glu-COO-, the carbonyl oxygen (in the peptide bond) of the histidine residue is hydrogen bonded to the amide nitrogen of _______. (A) Trp(B) Lys(C) Val(D) Gln(E) Leu

63. The carbohydrate moiety is always attached to glycoproteins through _______. (A) aspartate, glutamate or tyrosine(B) tryptophan, glutamine or alanine (C) cysteine, phenylalanine or histidine(D) asparagine, serine or threonine (E) valine, leucine or isoleucine