71. Which compound is not one-carbon carrier in metabolism?
(A) tetrahydrobiopterin
(B) formyl-tetrahydrofolate
(C) methyl-tetrahydrofolate
(D) biotin
(E) S-adenosylmethionine

67. Cooperative binding of a ligand to a protein is a form of allosteric binding. Which of the following statements is false? (A) It is usually associated with proteins with multiple subunits. (B) The binding of one ligand affects the affinities of other unfilled binding sites. (C) The Hill plot results in a hyperbolic curve. (D) It results in a sigmoidal binding curve. (E) Hill coefficient (nH) is a measure of the degree of cooperativity.

68. Ubiquitin is a small protein which is covalently linked to proteins designated for destruction via ____. (A) ATP-dependent proteases in lysosomes (B) ATP-dependent proteases in proteasomes (C) ATP-dependent proteases in ribosomes (D) ATP-independent proteases in endosomes (E) ATP-independent proteases in peroxisomes

69. What of type reaction promotes the conversion of phosphatidylserine to phosphatidylethanolamine? (A) transamination (B) acetylation (C) dehydrogenation (D) methylation (E) decarboxylation

70. What compound does not exist in the glyoxylate cycle? (A) citrate (B) α-ketoglutarate (C) isocitrate (D) malate (E) oxaloacetate

72. Which of the following statements regarding yeast two-hybrid analysis is false? (A) The goal is to bring together the DNA-binding domain and the activation domain of the yeast Gal4 protein. (B) Gal4 protein has two domains: one that binds a specific DNA sequence domain, the other activates RNA polymerase to synthesize tRNA from an adjacent gene (reporter gene). (C) A library can be set up to fuse to the Gal4 protein DNA-binding domain. (D) The interacting protein can be quickly identified by DNA sequencing of the fusion protein′s gene. (E) Some false positive results occur, due to the formation of multiprotein complexes.

73. What amino acid residues in some membrane-associated proteins are covalently linked to myristoyl or farnesyl groups? (A) asparagine and lysine (B) cysteine and glycine (C) serine and tyrosine (D) asparagine and serine (E) proline and lysine

74. What main component in plasma membrane has the oligosaccharide head groups to determine human blood types (O, A, B, and AB)? (A) caveolin in lipid raft (B) clathrin in apical surface (C) sphingolipid (D) phospholipid (E) cholesterol

75. What enzyme is frequently used for the measurement of the concentrations of glucose in blood? (A) glucokinase (B) glucose epimerase (C) glucose dehydrogenase (D) glucose dehydration (E) glucose oxidase

76. What two classes of enzymes play an important role in generating and propagating a recombinant DNA molecule in DNA cloning? (A) recombinases and DNA polymerase α (B) recombinases and DNA polymerase γ (C) restriction endonucleases and DNA ligases (D) restriction endonucleases and recombinases (E) restriction endonucleases and reverse transcriptase

77. Insulin exerts its action through plasma membrane receptors to regulate the level of blood glucose. An elevated insulin level in the blood _______. (A) results from a below-normal blood glucose level (B) inhibits glycogen synthesis in liver and muscle (C) stimulates synthesis of fatty acids in liver and triacylglycerols in adipose tissue (D) inhibits glucose uptake by liver (E) stimulates glycogen breakdown in liver