67. Which of the following statements about microRNAs (miRNAs) are CORRECT? ① miRNAs originate from exogenous dsRNA. ② miRNAs form a perfect complementary to its target mRNA. ③ Some miRNAs can functionally inhibit mRNA translation. ④ Some miRNAs can promote mRNA decay. ⑤ miRNAs are transcribed by RNA polymerase III.
(A) ①,⑤
(B) ②,③
(C) ③,④
(D) ②,④
(E) ③,⑤

63. A cell that is unable to synthesize or obtain tetrahydrofolate would probably be deficient in the biosynthesis of ______. (A) dGMP (B) dCMP (C) dAMP (D) dTMP (E) dUMP

64. Pompe disease is a glycogen storage disease caused by defect in ______. (A) glycogen phosphorylase (B) lysosomal α-1,4-glucosidase (C) glycogen branching enzyme (D) glucose-6-phosphatase (E) phosphorylase kinase

65. Which of the following statements about allosteric regulation are CORRECT? ① Substrate is a heterotropic allosteric modulator. ② Allosteric regulation can increase or decrease the catalytic activity of enzymes. ③Allosteric enzymes typically have oligomeric structure. ④ The activity of some allosteric enzymes is regulated by feedback inhibition. ⑤ Allosteric modulators cannot induce conformational change of allosteric enzymes. (A) ①,②,③ (B) ①,②,④ (C) ①,③,④ (D) ①,③,⑤ (E) ②,③,④

66. Which of the following statements about ribozyme are CORRECT? ① Peptidyl transferase is a ribozyme. ②Aminoacyl-tRNA synthetase is a ribozyme. ③ The substrate of ribozyme is RNA. ④ Hammerhead ribozyme is involved in trans-splicing reaction. ⑤ RNase P is a ribozyme. (A) ①,②,③ (B) ①,③,④ (C) ①,④,⑤ (D) ①,③,⑤ (E) ②,④,⑤

複選題68. Which of the following statements about glycogen is FALSE? (A) Glucose-6-phosphate is released from nonreducing ends of the glucose polymer by the action of the enzyme glycogen phosphorylase. (B) In glycogen breakdown, it involves sequential phosphorolytic cleavages of α(1→4) bonds. (C) Glycogen is the storage polysaccharide in skeletal and liver cells. (D) Glycogen is a polymer of glucose in α(1→4) linkages with α(1→6) linked branches. (E) The breakdown of glycogen in skeletal muscle ultimately enters glycolysis to generate ATP.

69. Which of the following statements for Shine-Dalgarno sequence are CORRECT? ① Shine-Dalgarno sequence is found in prokaryotic mRNA. ② Shine-Dalgarno sequence is a purine-rich sequence. ③ Shine-Dalgarno sequence can base-pair with a sequence of tRNA. ④ Shine-Dalgarno sequence is involved in DNA replication. ⑤ Shine-Dalgarno sequence can base-pair with a sequence of 16S rRNA. (A) ①,②,③ (B) ①,②,⑤ (C) ①,③,④ (D) ①,④,⑤ (E) ①,②,④,⑤

70. Which of the following statements about nitric oxide (NO) are CORRECT? ① Cellular NO is produced from lysine. ② Nitroglycerine is an NO donor. ③ Nitric oxide synthase is involved in the production of NO. ④ Adenyl cyclases are receptors for NO. ⑤ NO production in endothelial cells leads to vasodilation. (A) ①,②,③ (B) ②,③,④ (C) ③,④,⑤ (D) ①,③,④ (E) ②,③,⑤

71. Which of the following statements about oxidative phosphorylation are CORRECT? ① Oxidative of NADPH occurs in mitochondria. ② The production of ATP is driven by electron transport and proton gradient. ③ The process of chemiosmotic coupling is involved in the synthesis of ATP in mitochondria. ④The production of ATP is mediated by a substrate-level phosphorylation of ADP. ⑤ The electron transport is inhibited by 2,4-dinitrophenol. (A) ①,③,⑤ (B) ①,②,③ (C) ②,③ (D) ③,④,⑤ (E) ③,⑤

72. Which of the following statements about lac operon is CORRECT? ① The repressor is the protein product of lac Z gene. ② The lac operon can be turned on by β-galactoside. ③ Repressor binds to the operator and blocks the binding of RNA polymerase to promoter. ④ Isopropyl-β-D-thiogalactoside can bind to Lac repressor to turn on protein expression. ⑤ In the lac operon model, the genes within the operon will be expressed if lactose is present in E. coli. (A) ①,②,③ (B) ①,②,④ (C) ②,③,④ (D) ③,④,⑤ (E) ②,③,④,⑤

73. Which of the following statements about glutathione are CORRECT? ① Glutathione is an antioxidant. ② Glutathione is a tetrapeptide. ③ Glutathione is not involved in detoxification of xenobiotics. ④ The biosynthsis of glutathione synthesis occurs as a part of γ-glutamyl cycle. ⑤ Oxidized glutathione is reduced by glutathione reductase. (A) ①,②,③ (B) ①,③,④ (C) ①,④,⑤ (D) ②,③,④ (E) ①,②,⑤