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Unformatted text preview: More Questions from Past Tests 1. Which of the following statements describes the code that directs accurate replication and transcription of DNA? A. Synthesis of polynucleotide strands by DNA and RNA polymerases in the 5' to 3' direction. B. Nucleotide sequence of template strands. C. Antiparallel orientation of complementary strands. D. Reading of templates by DNA and RNA polymerases in the 3' to 5' direction. E. Complementary base pairing. The figure shown below shows some of the essential components of a bacterial translation-initiation complex formed by the 30S ribosomal subunit. Use their labels, A E , to associate them with their names given under 27 31 . 2. Ribosomal A site 3. IF-1 4. Ribosomal P site 5. IF-2 6. N-formyl methionine Listed below under A E are five codons. From this list, pick the codon that fits each of the statements listed under 7 12 . A. UGA B. AUG C. UGG D. UAA E. UAG 7. In the universal genetic code, this codon causes termination of translation, but in some Bacteria and many Archaea , it directs the insertion of pyrolysine into polypeptides. 8. In the universal genetic code, this is the only codon for tryptophan. 9. In the universal genetic code, this codon causes temination of translation, but in the genera Mycoplasma and Phycoplasma of the Bacteria, this codon directs the insertion of tryptophan into nascent polypeptides. 10. So far, this is the only translation-termination codon that appears to have no alternate function in any organism. 11. If located 6 to 9 nucleotides downstream of a Shine Dalgarno sequence on a bacterial mRNA, this codon is used to bind tRNA fMet to the P site of 30S ribosomal subunits. 12. At internal locations in ORFs, this codon specifies insertion of methionine into polypeptides. 13. A culture of wild-type E. coli was started from ~10 3 rifampin-sensitive (Rif S ) cells and allowed to grow to a final population of 10 9 cells. At this point, all the cells were spread in Petri dishes on medium containing rifampin (Rif) and incubated overnight. The next day, a total of 36 colonies had grown on the Rif medium. The approximate rate of mutation of rif s to rif r is: A. 3.6 10 ! 6 B. 3.6 10 ! 7 C. 3.6 10 ! 8 D. 3.6 10 ! 9 E. 3.6 10 ! 10 14. A din gene is A. any gene that conveys antibiotic-resistance....
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This note was uploaded on 05/01/2010 for the course MMG 431 taught by Professor Bertrand during the Spring '08 term at Michigan State University.
- Spring '08