複選題

23. Which of the following statements about "the genetic code" is/are TRUE?
(A) Some codons do not specify an amino acid.
(B) Some amino acids share the same codon.
(C) The first two nucleotides of a codon are often enough to specify a given amino acid.
(D) Nearly all organisms use the same genetic code.
(E) The initiation codon specifies methionine.

19. Which element(s) are trans-acting? (A) 1 (B) 2 (C) 3 (D) 4 (E) 5

20. Which element is the repressor? (A) 1 (B) 2 (C) 3 (D) 4 (E) 5

複選題21. Which of the following statements about "Transcription" is/are TRUE? (A) Transcription factors function to help move ribosomes along the mRNA. (B) The release of pyrophosphate from a nucleoside triphosphate drives the reaction. (C) RNA is synthesized from the 5' end to the 3' end. (D) Transcription requires the use of a primer. (E) DNA to RNA base pairing includes A to U and G to C.

22. In prokaryotic RNA synthesis (A) the rate of incorporation of nucleotides is constant throughout the elongation process (B) the p (rho) protein is always required for termination (C) a unique series of three bases leads to termination (D) inverted-repeat sequences in the DNA being transcribed can lead to termination (E) the sigma (6) subunit stays with the RNA Polmerase throughout synthesis.

複選題24. Which of the following elements can function as "eukaryotic promoters"? (A) a TATA box. (B) an initiator element. (C) CpG islands. (D) an enhancer. (E) silencers.

複選題25. Which of the following is/are category for the gene product for an Oncogene? (A) Glycolytic enzyme. (B) Transcription factor. (C) Housekeeping gene. (D) Nonreceptor protein kinase. (E) Growth factor receptor.

複選題26. A mutant bacterium is isolated. This bacterial strain has the characteristic of very slow, "sickly" growth. You isolate mRNA from this bacteria to use in an in vitro translation system and note that even in vitro it is difficult to use this message and obtain protein. Of the following, which is/are likely explanation for these results? (A) There may be a mutation in the ribosomal rRNA recognizing the Shine-Delgarno sequence of the message. (B) In this mutant, the ribosomal subunits may not associate well enough for effective translation. (C) This mutant may have altered tRNA molecules, such that the codon-anticodon interaction during translation is affected. (D) These bacteria may not manufacture enough translation factors for effective translation. (E) There may be a mutation in the Shine-Delgarno sequence of the DNA, resulting in a RNA that poorly binds the ribosome.

27. 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) associated with response to distinct events. (B) not constitutive. (C) "activated" by particular signals (induced). (D) "turned off" by particular signals (repressed). (E) None of the above.

28. In a histone protein, what modification(s) to lysine mark the nucleosome as a transcription target? (A) alkylation (B) acetylation (C) phosphorylation (D) methylation (E) ubiquitylation

29. microRNAs play a key role in which of the following? (A) repressed translation of the mRNA. (B) degradation of viral RNA (C) rapid translation of the mRNA. (D) degradation of the mRNA (E) repeated translation as the miRNA prevents destruction of the mRNA