Exam 3A with Solution Manual | Molecular Genetics | MCB 250, Exams of Molecular biology

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NETWORK ID:. SECTION: MCB250 - Exam HI Form A November 12, 2008 Multiple Choice: Choose the BEST answer from the choices A-E. Each question is worth 5 points. Please read all questions carefully! L. During conjugation between bacteria: A. Double stranded DNA is transferred to the recipient B. Transposons present on the incoming DNA may be activated to transfer to the recipient chromosome. Bacteriophage components are used to build a bridge between the donor and recipient cells. RecA is required for the process. Homologous DNA but not foreign DNA can be inherited by the recipient cells. 2. The mechanisms by which replicative and non-replicative transposons transpose differ in that: A. Replicative transposons form an RNA-DNA hybrid during the replication phase of transposition. B. Non-replicative transposons use a serine/threonine-type recombinase while replicative transposons use a DDE-type recombinase. Replicative transposition results in fused replicons while non-replicative transposition results in a double-strand break in the donor replicon. Replicative transposons are bounded by direct repeats while non- replicative transposons are bounded by indirect repeats. The transposase complex of replicative transposons makes a flush-end double-stranded set of cuts at the target site in the recipient replicon while the transposase complex of non-replicative transposons makes a staggered set of cuts in the target site of the recipient replicon.