5. Rolling circle replication ________.
(A) begins when the origin of replication is pulled apart to generate a replication bubble
(B) occurs at the origin of vegetative replication
(C) begins when the origin of replication is nicked and one strand is unrolled
(D) occurs when a plasmid replicates in step with host cell division
(E) occurs bidirectionally that can rapidly synthesize multiple copies

1. Chi sites are _________. (A) generated from Holliday junctions (B) inverted repeats (C) binding sites for RecA protein (D) specific sequences in prokaryotic genomes where crossovers occur (E) specialized single-stranded region

2. A single nucleotide deletion occurred in a gene. The change is indicated below. What is the consequence of the mutation? ......AGT CGA TGA GTT AGC CTA...... → ......AGT CGA TGG TTA GCC...... (A) The mutation occurs in the third position of a codon so it is likely to be a silent mutation because of the Wobble effect. (B) It leads to frameshift so the downstream amino acid sequence will alter and the protein is unlikely to be functional. (C) It results in premature termination of translation so a truncated polypeptide will be produced. (D) A longer polypeptide will be made but the protein might still be functional. (E) It changes the single amino acid, which may or may not cause a problem.

3. What is the purpose of the inverted repeats at the ends of DNA-based transposons? (A) The inverted repeats are recognized by enzymes that move the elements. (B) The inverted repeats are the sites of transfer. (C) The inverted repeats are recognized by restriction enzymes that cut out the transposon. (D) The inverted repeats are magnets for nucleases. (E) The inverted repeats protect transposons from degradation.

4. What is 5' UTR? (A) 5' untranscribed region: it refers only to the promoter region. (B) 5' untranscribed region: it includes promoter and enhancer. (C) 5' untranscribed region: it regulates transcription activity. (D) 5' untranslated region: it is removed during RNA splicing. (E) 5' untranslated region: it must contain the first exon.

複選題6. Regarding molecular cloning using restriction enzyme and ligase. (A) Blunt end is clean and thus easier to be ligated. (B) Ligase also mediates joining of sticky ends by catalyzing the formation of hydrogen bonds. (C) Two sticky ends with complementary overhangs can be perfectly ligated but the restriction enzyme recognition site is not necessarily restored. (D) Restriction enzyme more efficiently cuts at the ends of DNA fragments. (E) Phosphatase treatment of both digested vector and digested insert reduces self-ligation so that correct ligation is enhanced.

7. The size of a gene in the genome is 3kb. What is the expected size of the polypeptide product encoded from the 3kb sequence? It appears as a single 60kD band on a SDS-PAGE gel. What could be the explanation for the difference? (A) 110kD； presence of introns (B) 110kD； protein degradation (C) 55kD； post-translational modifications (D) 55kD； amino acid composition bias (E) 30kD； dimer formation

複選題8. Which of the following factor(s) promote dissociation of 70S ribosome to 50S and 30S? (A) IF-2 (B) IF-3 (C) EF-Tu (D) EF-G (E) RRF

9. Which of the following factor(s) mediates the binding of the Shine-Dalgarno sequence with the complementary sequence of the 16S rRNA? (A) IF-2 (B) IF-3 (C) EF-Tu (D) EF-G (E) RRF

10. Which of the following descriptions is NOT correct for comparison of protein translation between eukaryotes and bacteria? (A) Bacterial translation begins with methionine (B) Bacterial translation requires Shine-Dalgarno sequence to show ribosomes where to start (C) Eukaryotic mRNA has caps at 5'end (D) Eukaryotic initiating tRNA is not same as tRNA for interior (E) Eukaryotic translation requires Kozak sequence to show ribosomes where to start

複選題11. Which of the following factor(s) can bind Pab1p, a poly[A]-binding protein? (A) eIF1 (B) eIF1A (C) eIF4A (D) eIF4E (E) eIF4G