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.

5. Which of the following DNA polymerases removes primers in Escherichia coli? (A) DNA polymerase I. (B) DNA polymerase II. (C) DNA polymerase III. (D) DNA polymerase IV. (E) DNA polymerase V.

6. Which of the following statements is correct regarding the replication folk? (A) Topoisomerase acts to separate two strands of duplex DNA. (B) Synthesis of the two strands of DNA is not simultaneous. (C) The lagging strand is the strand on which the polymerase moves in the same direction as the movement of the replication fork. (D) The DNA fragment formed on the lagging strand is called the Okazaki fragment. (E) Primase acts to join breaks in the phosphodiester backbone of DNA.

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.

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.

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.

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.