43. The ligands for peroxysome proliferator-activator receptor (PPAR) belong to which of the following categories.
(A) protein
(B) vitamin
(C) fatty acid
(D) amino acid
(E) carbohydrate

39. Which of the following reactions is most likely catalyzed by a   ligase  ? (A) A+ H2O ←→P+Q (B) A + B + ATP ←→ P + ADP + (C) A ←→ P+Q (D) A + ←→P + NADH (E) A + ATP ←→ P + ADP

40. To measure the "rate" of an enzymatic reaction, you need to plot (A) "substrate concentration" vs "time" (B) "initial rate" vs "substrate concentration" (C) "initial rate" vs "time" (D) "initial rate" vs "product concentration" (E) "free enzyme concentration" vs "time"

41. When [S] increases from 2Kᴍ to 4Kᴍ, the initial velocity (Vo) of an enzyme catalyzed reaction increases by a factor of _____ (Assuming this enzyme follows the Michaelis-Menton kinetics.) (A) 0.9 (B) 1.0 (C) 1.1 (D) 1.2 (E) 1.4

42. Inhibitor "X" was found to decrease the Vmax (maximum velocity) of an enzymatic reaction. Therefore, "X" can be classified as a _____ (A) competitive inhibitor (B) uncompetitive inhibitor (C) mixed inhibitor (D) uncompetitive inhibitor or mixed inhibitor (E) competitive inhibitor or mixed inhibitor

44. Cholera toxin, a protein produced by a gram-negative bacterium vibrio cholerae, is responsible for the characteristic symptoms of cholera: extensive loss of body water and Na⁺ through continuous, debilitating diarrhea. If body fluid and Na⁺ are not replaced, severe dehydration results； untreated, the disease is often fatal. What is the effect of cholera toxin in the intestinal cells? (A) Increase GTP hydrolysis. (B) Persist activation of G protein. (C) Increase the degradation of cGMP. (D) Increase the rate of phophatidylinositol turnover. (E) Open the chloride channels on the membrane of intestinal cells. 

45. According to the description, which of the following compounds could illicit proliferation signaling in smooth muscle cells? (A) thrombin (B) vitamin K (C) interferon (D) cholesterol (E) retinoic acid

複選題46. After the ligand binding to PAR, which of the following events will happen? (A) The receptors form dimer on the membrane. (B) The receptors will be tyrosine-phosphorylated. (C) The receptor will dimerize with RXR and illicit gene transcription. (D) It activates GTP binding proteins and increase calcium mobilization. (E) It contains DNA- and ligand-binding domains in distinct region of PAR.

47. Some hormones are derived from amino acids； for example, catecholamines are derived from while NO is derived from _____ (A) tyrosine； arginine (B) tryptophan； lysine (C) tyrosine； histidine (D) tryptophan； arginine (E) histidine； lysine

48. Hormone-activated phospholipase C can convert phosphatidylinositol 4,5-bisphosphate to: (A) diacylglycerol + inositol triphosphate. (B) diacylglycerol + inositol + phosphate. (C) glycerol + inositol + phosphate. (D) glycerol + phosphoserine. (E) phosphatidyl glycerol + inositol + phosphate.

49. The force that drives an ion through a membrane channel depends upon: (A) the charge on the membrane. (B) the difference in electrical potential across the membrane. (C) the size of the channel. (D) the size of the ion. (E) the size of the membrane.