9. A mutation that inactivates a regulatory gene of a repressible operon in an E. coli cell would result in _____.
(A) continuous transcription of the structural gene controlled by that regulator
(B) irreversible binding of the repressor to the operator
(C) complete inhibition of transcription of the structural gene controlled by that regulator
(D) continuous translation of the mRNA because of alteration of its structure
(E) defects in cell division

5. What is the mechanism of information transfer in eukaryotes? (A) Messenger RNA is transcribed from a single gene and transfers information from the DNA in the nucleus to the cytoplasm, where protein synthesis takes place. (B) Transfer RNA takes information from DNA directly to a ribosome, where protein synthesis takes place. (C) DNA from a single gene is replicated and transferred to the cytoplasm, where it serves as a template for protein synthesis. (D) Proteins transfer information from the nucleus to the ribosome, where protein synthesis takes place. (E) Retrovirus-mediated gene transfer can only occur prenatally during pregnancy

6. Which of the following occurs in prokaryotes but not in eukaryotes? (A) post-transcriptional splicing (B) translation in the absence of a ribosome (C) concurrent transcription and translation (D) gene regulation (E) alanine can be added to polypeptide chain by tRNA with different codons

7. A ribozyme is  _____.(A) a catalyst that uses RNA as a substrate (B) an enzyme that synthesizes RNA as part of the transcription process (C) an enzyme that catalyzes the association between the large and small ribosomal subunits (D) an RNA with catalytic activity (E) an important component of RNA transport from nucleus to cytoplasm.

8. A mutant bacterial cell has a defective aminoacyl-tRNA synthetase that attaches a lysine to tRNAs with the anticodon AAA instead of the normal phenylalanine. The consequence of this for the cell will be that _____.(A) the positions of phenylalanine in proteins will still encode phenylalanine (B) the cell will compensate for the defect by attaching phenylalanine to tRNAs with lysine-specifying anticodons (C) the cell is not able to synthesize lysine (D) the ribosome will skip a codon every time a UUU is encountered (E) proteins in the cell will include lysine instead of phenylalanine at amino acid positions specified by the codon UUU

10. The primary difference between enhancers and promoter-proximal elements is that enhancers _____.(A) enhance transcription; promoter-proximal elements inhibit transcription (B) are transcription factors; promoter-proximal elements are DNA sequences (C) are at considerable distances from the promoter; promoter-proximal elements are close to the promoter (D) are DNA sequences; promoter-proximal elements are also DNA sequences (E) are only identified in eukaryotic cells but not in prokaryotic cells.

11. To introduce a particular piece of DNA into a plant, you would most likely be successful with which of the following methods? (A) construction of a recombinant lambda phage carrying the specific DNA. (B) introducing a plasmid into the cell (C) infecting the plant cell with a Ti plasmid (D) transcription and translation (E) electroporation followed by recombination

複選題12. Which of the following status may reflect what we know about how the flu virus moves between species? (A) An animal such as a pig is infected with more than one virus, genetic recombination occurs, the new virus mutates, the virus is passed to a new species such as a bird, and the virus mutates again and can now be transmitted to humans. (B) The flu virus in a pig is mutated and replicated in alternate arrangements so that humans who eat the pig products can be infected. (C) An influenza virus gains new sequences of DNA from another virus, such as a herpesvirus; this enables it to be transmitted to a human host. (D) A farmer is infected by human flu and chicken flu viruses at the same time and the recombinant virus could become highly contagious and virulent for human. (E) There is no avian flu virus can directly infect human.

複選題13. Please select all the correct description about M phase of cell cycle. (A) Cyclin dependent kinase 1 (Cdk1) is the key kinase regulate the progression of M phase. (B) Cellular DNA starts to replicate at M phase. (C) The nuclear envelope starts to break down at prophase. (D) The nuclear envelope starts to reorganize at nuclear port complex at telophase. (E) The nuclear pore complexes are completely disassembled into single molecules before M phase.

14. The product of the p53 gene _____.(A) causes cells to reduce expression of genes involved in DNA repair (B) inhibits the cell cycle (C) allows cells to pass on mutations due to DNA damage (D) slows down the rate of DNA replication by interfering with the binding of DNA polymerase (E) locates at the ribosome to ensure RNA translation efficiency

複選題15. Which of the following statements describes the lysogenic cycle of lambda (λ) phage are not correct? (A) The phage DNA is copied and exits the cell as a phage. (B) Most of the prophage genes are activated by the product of a particular prophage gene. (C) The phage genome replicates along with the host genome. (D) After infection, the viral genes immediately turn the host cell into a lambda-producing factory, and the host cell then lyses. (E) The lysogenic lambda can be induced into lytic cycle.