44. Which of the following statements about neurotransmitter is FALSE?
(A) Dopamine is derived from tyrosine and released by ventral tegmental area (VTA) neuron.
(B) Epinephrine derived from tryptophan is important for fight-or-flight reactions.
(C) Serotonin derived from tryptophan affect sleep and mood.
(D) Endorphin is a neuropeptide to mediate pain perception.
(E) Substance P is a neuropeptide to mediate pain perception.

40. Which of the following statements about the RNA processing is FALSE? (A) Not all of the nucleotides in the mature mRNA can be translated into proteins. (B) Spliceosomes are composed of proteins and snRNAs. (C) Modified guanosine is required for the capping of pre-mRNA. (D) Methylation is required for the capping of pre-mRNA. (E) PolyA polymerase adds 50-200 more adenines at the stop codon.

41. Which of the following statements about cell junctions is FALSE? (A) Actin filaments anchor desmosomes in the cytoplasm. (B) Hemidesmosomes connect cells to extracellular matrix (ECM) via integrins. (C) Integrin is a transmembrane protein with two nonidentical subunits. (D) Cadherins are Ca2+-dependent molecules to create cell-to-cell junctions. (E) The connexons of gap junctions allow the passage of ions.

42. Which of the following statements about blood tissue is FALSE? (A) The mature red blood cells contain nucleus in frog but not in human. (B) Eosinophils with bilobed-nucleus can kill parasites. (C) Lymphocytes with multilobed-nucleus are the most abundant leukocytes. (D) Monocytes are phagocytes and develop into macrophages. (E) Basophiles secret anticlotting factor called heparin at the site of injury.

43. Which of the following statements about gene cloning is FALSE? (A) DNA with specific palindromic sequence can be cut by restriction enzymes. (B) EcoRI, a restriction enzyme from E. coli, cut DNA into sticky ends. (C) Gene of interest can be linked into plasmid with DNA polymerase. (D) The plasmids are transformed into competent cells. (E) Ions such as CaCl2 affect whether or not a bacterium will be competent cells.

45. Which of the following statements about drugs is FALSE? (A) Taxol inhibits cancer cells by preventing microtubule depolymerization. (B) Tamoxifen inhibits cancer cells by blocking the function of estrogen receptor. (C) RU486 induces abortion by blocking the function of estrogen receptor. (D) Erythromycin inhibits the growth of bacteria by blocking their ribosomes. (E) Chloramphenicol inhibits the growth of bacteria by blocking their ribosomes.

46. Which of the following sugars contain ketone group? (A) glyceraldehyde (B) ribose (C) glucose (D) fructose (E) galactose

47. Which of the following proteins have quaternary structure? I. Methionine II. Lysozyme III. Collagen IV. Hemoglobin (A) I and II (B) III and IV (C) I, II, and IV (D) II, III, and IV (E) II and III

48. Endomembrane system includes following organelles, except ______. (A) nuclear envelope (B) endoplasmic reticulum (ER) (C) Golgi apparatus (D) mitochondria (E) lysosome

49. Which of following is NOT a second messenger in signal transduction? (A) proton (B) cAMP (C) Ca2+ (D) inositol triphosphate (IP3) (E) diacylglycerol (DAG)

50. All of the enzymes catalyze reactions to produce NADH , FADH2 or ATP in citric acid cycle, except ______. (A) isocitrate dehydrogenase (B) α-ketoglutarate dehydrogenase (C) succinyl-CoA synthetase (D) succinate dehydrogenase (E) citrate synthetase