63. Vitamin B1 (thiamine) is the precursor to the coenzyme thiamine pyrophosphate (TPP). Thiamine deficiency would decrease which one of the following enzyme activities?
(A) Fumarase
(B) Isocitrate dehydrogenase
(C) Malate dehydrogenase
(D) Succinate dehydrogenase
(E) α-Ketoglutarate dehydrogenase

59. HIV is the virus that causes AIDS. In the mid-1990s, researchers discovered an enzyme in HIV called protease. Once the enzyme's structure was known, researchers began looking for drugs that would fit into the active site and block it. If this strategy for stopping HIV infections were successful, it would be an example of what phenomenon? (A) allosteric regulation (B) competitive inhibition (C) vaccination (D) denaturation (E) synergistic effect

60. The Nobel Prize in physiology or medicine was awarded to Dr. Yoshinori Ohsumi for his discovery of mechanisms for _______________. (A) apoptosis (B) mitochondrial fusion and fission (C) vesicular transport (D) signal transduction in the nervous system (E) autophagy

61. In replication, which of the followings is used for polymerization of both leading strand and lagging strand? (A) DNA ligase (B) DNA polymerase I (C) DNA polymerase III (D) Gyrase (E) DNA helicase

62. Many coenzymes are derived from vitamins. Which of the following statements are correct? ① FAD is derived from vitamin B6. ② Pyridoxal phosphate is derived from vitamin B1. ③ Coenzyme A is derived from pantothenic acid. ④ 5’-Deoxyadenosyl cobalamin is derived from vitamin B12. ⑤ NAD is derived from nicotinic acid. (A) ①②③ (B) ②③④ (C) ③④⑤ (D) ①④⑤ (E) ①③⑤ 

64. Which one of the representations describes the oligopeptide shown below? (A) Tyr-Ala-Thr (B) Tyr-Ala-Ser (C) Phe-Ala-Thr (D) Phe-Gly-Cys (E) Phe-Ala-Tyr

65. Which of the following statements regarding Michaelis-Menten kinetic analyses of enzyme action are correct? ① The total enzyme concentration studied at each substrate concentration is fixed in analysis of enzyme kinetics. ② Formation of enzyme-substrate complex does not appreciably decrease the concentration of substrate. ③ cat reduces with competitive inhibition. ④ Maximal velocity is reached when the enzyme-substrate complex is equal to the total concentration of enzyme present. ⑤ The initial reaction velocity should be measured because most of the substrate has not been converted to product. (A) ①②③④ (B) ①②③⑤ (C) ①②④⑤ (D) ②③④⑤ (E) ①③④⑤

66. The high free energy change for the hydrolysis of a thiol ester, as found in acetyl-CoA, compared with that for the hydrolysis of a simple ester, is partly due to __________. (A) the greater resonance stability in a simple ester due to better π-electron overlap in a CO linkage than in a CS linkage (B) the gain in resonance energy in the product, acetate (C) the high value for the bond energy in S-C bond (D) reduction of the unfavorable electrostatic interaction in the acetyl-CoA (E) the high value for the bond energy in S-P bond

67. Phosphate (Pi) is transported into the mitochondria from the cytosol by a phosphate carrier which is driven by the ____________. (A) hydrolysis of ATP (B) simultaneous transport of H+ into the mitochondrion (C) simultaneous transport of ADP into the mitochondrion (D) simultaneous transport of H+ out of the mitochondrion (E) simultaneous transport of ATP out of the mitochondrion

68. Which of the following statements regarding metabolism is NOT correct? (A) The metabolism can be classified as either catabolic or anabolic reactions. (B) Enzymes are usually required for cells to carry out reaction under condition of moderate temperature, pressure, and pH. (C) Glucose, fatty acids, and some amino acids are reduced to form acetyl-CoA, which enters the citric acid cycle. (D) The energy of metabolism is used to synthesize ATP from ADP and Pi. (E) Reactions occur spontaneously only when the free energy change is negative.

69. Which of the following statements about membrane proteins are correct? ① Membrane proteins can be extracted from cell membrane using sodium dodecyl sulfate. ② Integral proteins can span the membrane with α-helical structure or β-sheet structure. ③ Estrogen receptor is a membrane protein. ④ The membrane proteins are not associated with membrane through glycosylphosphatidylinositol anchor. ⑤ The transmembrane helix of membrane proteins can be predicted from hydropathic index of amino acid sequence. (A) ①②③ (B) ①②⑤ (C) ①②④ (D) ②④⑤ (E) ①③④