複選題

12. The p300/CBP (CREB-binding protein) coactivator proteins are histone acetyltransferases that help regulate the transcription of many genes. Based on this information, these proteins are involved in
(A) DNA acetylation.
(B) chromatin remodeling.
(C) recruitment of RNA polymerase II.
(D) formation of the transcription initiation complex.

8. If you were able to look very closely at a portion of DNA and find methylated histones, you would (A) be mistaken since only DNA can be methylated, not histones. (B) be looking at a region of active chromatin. (C) be looking at a region of inactive chromatin. (D) be looking at transcription initiation.

9. A mutation in one gene that counteracts the effects of a mutation in another gene is known as a (A) temperature-sensitive mutation. (B) recessive mutation. (C) conditional mutation. (D) suppressor mutation.

10. You are studying the function of a recently identified gene in C. elegans. You have been performing genetic screens for several months in an attempt to isolate loss-of-function mutations in this gene, but unfortunately you have been unsuccessful. Your advisor suggests that you try another approach to eliminate gene function. Which of the following techniques would accomplish this goal? (A) Design a repressor to bind to the operon of this gene. (B) Use a histone deacetylase to induce a transcriptionally inactive state. (C) Use a C. elegans strain with a homozygous TFIID mutation to prevent the translation initiation complex from forming. (D) Use RNA interference to prevent mRNA translation.

11. Which of the following statements regarding the ubiquitin-proteosome pathway is false? (A) This pathway is used to regulate expression of a number of cell surface receptors. (B) When proteins are destroyed by the proteosome, the ubiquitin moiety is not destroyed, but rather cleaved off and reused. (C) Ubiquitin ligase adds ubiquitin residues to targeted proteins in a stepwise fashion. (D) Ubiquitination of a targeted protein requires only one molecule of ATP.

13. The polymerase chain reaction (PCR) technique can be used for (A) direct isolation of a specific segment of genomic DNA. (B) preparation of probes. (C) synthesis of RNA from genomic DNA. (D) a and b (E) all of the above

14. In the large-scale production of a particular human protein in E. coli cells, the cDNA corresponding to the protein was modified so that the expressed protein would have six histidine residues at the C-terminus. The purpose of this modification was (A) to facilitate transfer of the cDNA into the E. coli cells. (B) to provide a promoter for the transcription of the cDNA in E. coli. (C) to facilitate purification of the expressed protein though binding to an affinity column. (D) to prevent degradation of the expressed protein by E. coli proteases.

15. The ability of DNA to denature is important for which process? (A) DNA synthesis (B) nucleic acid hybridization experiments (C) RNA synthesis (D) all of the above

16. Which of the following is not required for both DNA replication and RNA transcription? (A) DNA (B) primers (C) RNA (D) proteins

複選題17. Which of the following lead(s) to a point mutation? (A) deamination of a cytosine base into a uracil base in the open reading frame (B) A change from a TAA codon to a TAG codon in the coding region (C) A sequence change in the 3' untranslated region (D) A loss of a T in the coding region (E) all of the above

18. You are performing an experiment to assay phosphorylation of a substrate by a protein kinase. Based on the data in the table below, what do these experimental results suggest?(A) GTP is not required for phosphorylation. (B) The substrate can undergo autophosphorylation. (C) The substrate is not required for phosphorylation. (D) The protein kinase is required for phosphorylation.