9. Attenuation of Trp operon is performed by
(A) binding of ribosome to 5'-UTR
(B) pairing of helices 3/4 of leader peptide
(C) pairing of helices 2/3 of leader peptide
(D) pairing of 5'-UTR and leader peptide

5. The one recombinase employed in the bacteria homologous recombination is _____  (A) RecA (B) CRE recombinase (C) Flippase (D) Spo11

6. The transposition of _____ element involves a RNA encoded genome stage. (A) P-element (B) Tn10 (C) Tyl (D) Tn3

7. Mismatch repair of newly replicated DNA can be facilitated by _____ . (A) nicking of the parental strand in bacteria (B) nicking ofthe nascent strand in prokaryotes (C) methylation of the GATC in parental strand in eukaryotes (D) methylation ofthe GATC in parental strand in prokaryotes

8. A graduate student accidentally cloned a cDNA from an economically important animal whose genomic sequence has not been resolved. The sequence of this cDNA can be summarized as below: 5'-gegatagtataatatcggccaggATGccg..ggccgggtattctcatttTAAggcaggttctta-3 The start and stop codons are shown in bold capital. If he/she likes to amplify the coding region ofthis gene, which one of the following PCR primer sets will work for him/her? (A). 5'-cggccaggATGccg-3'/5'-ttctcatttTAAggcaggttctta-3 (B). 5'-gccggtcCTAcggc -3'/5'-ttctcatttTAAggcaggttctta-3 (C). 5'-cggccaggATGccg-3'/5'-taagaacctgccTTAaaatgagaa -3 (D). 5'-gccggtcCTAcggc -3'/ 5'-aaaATTccgtccaagaat -3

10. Okazaki fragments can be found at _____. (A) transating mRNA (B) transcribing rRNA (C) leading strand of replicating DNA(D) laggering strand of replicating DNA

11. The genomic organization of a gene with 3 exons is shown below. The exons are shown as 3 boxes and their boundaries are denoted according to their location in mRNA. The size of the introns as well as location of start and stop codons are also shown on the top. If one wants to detect its expression level with the primer set a/h, what will be the closest size of its PCR product? (A) 15 kb (B) 500 bp (C) 10 kb (D) 800 kb ATG TAA +1 +500 10 kb +501 +1100 +1101 +1400 20 kb

12. Following question 11, the part of exon 1 between TAA and +1400 is called as: (A) terminator (B) 5'-UTR (C) 3'-UTR (D) initiator

13. Reverse transcriptase is an enzyme that can use RNA as a template to synthesize single strand DNA. As like all DNA polymerase, it needs a primer for the initiation of polymerization. If one wants to detect the expression levels of several protein-coding genes in mammalian cells with RT-PCR, which of the following primers is best for his reverse transcription reaction? (A) 5'-AAAAAAAAAAAAAAA-3' (B) 5'-TTTTTTTTTTTTTTT-3 (C) 5'-TATATATATATATATA-3 (D) 5'-ATGATGATGATGATG-3

14. Which of the following elements/genes is not included in the immunity region of lambda phage genome? (A)(B)cl (C) (D)CII

15. The_____element in the chromosome can stop the spreading of heterochromatin and prevent the effect of an enhancer on genes located on other side. (A) insulator (B) promoter (C) centromere (D) initiator