34. Which of the following mobile elements is a retrotransposon?
(A) yeast Ty element
(B) bacterial IS sequence
(C) Drosophila P element
(D) maize activator (Ac) element
(E) RNA genome of influenza H7N9 virus

複選題30. Which of the following statements is/are TRUE? (A) Restriction endonucleases can cut DNA and RNA. (B) It is common to use ddNTPs (dideoxyribonucleoside triphosphates) in DNA sequencing. (C) Enzymes that seal nicks in DNA are called ligases. (D) In recombinant DNA technology, a YAC is an enzyme isolated from a large South American four-legged mammal. (E) The "c" in cDNA stands for Circular.

31. Which property of DNA is crucial for the conservation of genetic information? (A) antiparallelism (B) semiconservative replication (C) the ability to form a circular DNA (D) base-pair complementarity (E) The amount of A is the same as the amount of C

複選題32. The ability of DNA to denature is important for which process? (A) DNA synthesis (B) nucleic acid hybridization experiments (C) RNA synthesis (D) PCR reaction (E) DNA separation by agarose gel electrophoresis

33. Which of the following is required for both DNA replication and RNA transcription? (A) DNA (B) primers (C) RNA polymerase (D) phosphodiesterase (E) topoisomerase

複選題35. Which of the following is correct for the eukaryotic chromosomes? (A) The ends of eukaryotic chromosomes are called telomeres, and contain special repeat sequences, called telomeric sequences. (B) Telomere terminal transferase containing the reverse transcriptional activity is important to maintain the chromosomal ends in eukaryotes. (C) The centromeric sequences are important for proper chromosome segregation during replication. (D) Kinetochores assemble at the centrosome. (E) Telomerase activity declines with age and this could explain why cells lose their ability to divide after many replications.

複選題36. For the DNA replication in E. coli, which of the following is correct? (A) The leading strand is initially synthesized as Okazaki fragments (B) It has the DNA strand synthesized in a 5'-3' direction (C) DNA polymerase I adds nucleotides to the primer strand (D) The leading strand is synthesized continuously (E) It synthesizes each strand in the opposite direction (one 5'->3', one 3'->5'), so they can be synthesized at once.

37. A mutation that changes the recognition sequence for the restriction enzyme EcoRI from GAATTC to GATTTC is an example of a (A) restriction fragment length polymorphism (RFLP). (B) single nucleotide polymorphism (SNP). (C) simple sequence repeat (SSR). (D) genetic heterogeneity (E) none of the above

38. When a segment of DNA duplicates, causing two or more copies of a gene to be present in the chromosome, the most unlikely fate of the duplicate(s) would be (A) to lose function in subsequent mutation. (B) to improve function in subsequent mutation. (C) to gain a new function in subsequent mutation. (D) to become a pseudogene. (E) to become part of a gene family.

39. There are 45 different kinds tRNA (anticodons) available to serve as amino acid carriers, but there are 64 mRNA codons. Why aren't the tRNA anticodons and mRNA codons equal in number? (A) The reason is that the third base pair on the tRNA allows some flexibility (wobble); thus, some tRNA anticodons can recognize more than one mRNA codon. (B) The reason is that some tRNA anticodons can misread some of the mRNA codons, which creates a "wobble" in the tRNA anticodons that can be repaired by RNA repair enzymes. (C) The reason is that the third base pair on the mRNA codon allows some flexibility (wobble); thus, some tRNA anticodons can recognize more than one mRNA codon. (D) The reason is that the tRNA has the flexibility to choose which mRNA codons are necessary for building the polypeptide chain. (E) This broader recognition occurs because of the nonstandard pairing between bases in the wobble position corresponding to the 3' base in the mRNA and the complementary 5′ base in the tRNA anticodon.

40. Which one of the following statements comparing the human and mouse genomes is false? (A) Human and mouse have about the same number of genes. (B) The human genome shares 99% of its genes with the mouse. (C) A comparison of genomes confirms that mouse and humans shared a common ancestor more recently than humans and pufferfish. (D) Mitochondrial DNA is paternally inherited in both human and mouse. (E) Little rearrangement of genes has occurred in the two genomes.