43. In eukaryotes, the 3' end of the mRNA is important in the initiation of translation because
(A) it contains Kozak sequences that aid in initiation.
(B) translation occurs in the 3' to 5' direction.
(C) elF4A is attached to the 3' cnd and removes any sccondary structure that might prevent translation.
(D) the 3' poly( A ) tail and PABP bind initiation factor elF4G, stabilizing the 5' end of the mRNA.

39. An isolate of a mutant bacterium appears to grow more slowly than the wild-type popuiation from (which it was isolated. Further studies showed that the slower growth was due to a markedly reduced DNA polymerase I activity. From this information, one would expect that this organism would also be deficient in the activity of DNA (A) excision repair. (B) recombination. (C) transcription. (D) translation.

40. Which of the following molecules can be considered a final product in the flow of genetic information within a cell? (A) DNA (B) RNA (C) Protein (D) Protein or RNA can be the final product of a gene.

41. Which of the following is not a reason for the importance of mRNA processing in eukaryotes? (A) Longevity in the cytoplasm (B) Coupling of transcription and translation (C) Turnover in the cytoplasm (D) Removal of introns

42. Of the following steps associated with translation, which does not involve hydrolysis of GTP? (A) Aminoacylation oftRNA (B) Formation of the initiation complex (C) Binding of the aminoacyl tRNA to the codon at the A site (D) Translocation of the ribosome

44. Which of the following statements is not true concerning peptidyI transferase? (A) It is a ribozyme having catalytic activity. (B) It catalyzes peptide bond formation. (C) It moves the ribosome, so translation continues. (D) It is associated with the large subunit of ribosomes.

45. Gene knockdown via RNAi relies on the ability of eukaryotic cells to (A) degrade target mRNAs that are complementary to introduced dsRNA. (B) induce microRNA expression under particular conditions. (C) preferentially degrade mutated mRNAs. (D) inhibit transcription of sets of genes based on the presence of distal control elements.

46. You are working with a gene associated with an essential pathway that is necessary at two time points in an organism's lifetime. With regard to gene regulation, you would expect the gene to be (A) constitutive. (B) associated with response to distinct events through induction and repression signals. (C) induced by particular signals. (D) repressed by particular signals.

47. The amount of a protein in a cell is regulated by the rate of (A) transcription of its gene. (B) translation of its mRNA. (C) degradation of the protein. (D) All of the above

48. Release of RNA polymerase II to initiate transcription appears to be the direct result of the (A) binding of TAFs to the polymerase. (B)unwinding of the DNA by helicases. (C) phosphorylation of RNA polymerase by a protein kinase. (D) removal of the nucleosome occupying the promoter site.

複選題49. What are some diseases caused by vitamin deficiencies that affect the pyruvate dehydrogenase complex and a-ketoglutarate dehydrogenase complex? (A) vit. B1– cheilosis, angular stomatitis (B) niacin –pellagra (C) pantothenic acid – fatigue, insomnia, depression, irritability (D) riboflavin – Wernicke-Korsakoff syndrome, beriberi