11.Which of the following is the correct pair between the recombinase and the recombination site?
(A) Bacteriophage X integrase: res site.
(B) Phage P1 Cre: lox site.
(C) Escherichia coli XerC and XerD: att site.
(D) Yeast FLP: ori site.
(E) Salmonella Hin invertase: int site.

7.Telomerase: (A) solves the end replication problem of leading-strand synthesis. (B) uses endogenous DNA as template. (C) acts to extend the 3' end of the telomere. (D) synthesizes double-stranded DNA. (E) is present in all the eukaryotes.

8.Direct uptake of exogenous naked DNA through the cell membrane is called: (A) conjugation. (B) injection. (C) infection. (D) transformation. (E) transduction.

9.Which of the following is the correct pair between the type and the cause of DNA damage? (A) Thymine dimer: ethidium bromide. (B) Depurination: 5-bromouracil. (C) Deamination: ultraviolet illumination. (D) Double-strand breaks: y-radiation. (E) Deletion or addition of a base pair: nitrous acid.

10. Histones are subject to various modifications. Which of the following modifications does NOT appear in histones? (A) Methylation. (B) Phosphorylation. (C) Acetylation. (D) Ubiquitinoylation. (E) Carboxylation.

12. Which of the following complexes specifically recognizes Holliday junctions and promotes branch migration? (A) RecBCD complex. (B) UvrABC complex. (C) ClpPR complex. (D) RuvAB complex.(E) RhlAB complex.

13. Transcription initiation involves recognition of consensus sequences by specific regions/domains of the RNA polymerase in Escherichia coli. Which of the following regions or domains recognizes the -10 promoter element? (A) o factor region 2. (B) o factor region 3. (C) o factor region 4. (D) C-terminal domain of subunit o. (E) N-terminal domain of subunit a.

14. The structural feature of mRNA at the intrinsic transcription terminator in prokaryotes is a hairpin structure followed by: (A) an A-rich sequence. (B) a C-rich sequence. (C) a G-rich sequence. (D) a U-rich sequence. (E) an AU-rich sequence.

15. Which of the following small nuclear ribonucleoproteins (snRNPs) recognizes the 5' splice site? (A) U1. (B) U2. (C) U4. (D) U5. (E) U6.

16. A special form of RNA editing found in the mitochondria of trypanosomes and mediated by guide RNAs is deletion and insertion of: (A) adenine. (B) uracil. (C) guanine. (D) cytosine. (E) inosine.

17. The Drosophila Dscam gene contains 48 alternative forms of exon 6. What is the mechanism for having only one exon 6 variant in the mature mRNA? (A) Splicing factors cannot bind to more than one splicing site due to steric hindrance. (B) Spliced mRNA with more than one exon 6 variant leads to nonsense-mediated RNA decay. (C) The docking site binds to only one selector sequence located upstream of the exon6 variant. (D) Each exon 6 variant contains different sequences at the splicing sites. (E) Only the exon 6 variant that recruits enough SR proteins is retained in the mature RNA.