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12.1 Genetic Material & Bacterial Gene Transfer β Test 1
Q1. In Griffith's experiment with Streptococcus pneumoniae, mice died when injected with:β A mixture of heat-killed S-strain and live R-strain
Q2. The transforming principle of Griffith's experiment was identified as DNA by:β Avery, MacLeod and McCarty
Q3. The Hershey-Chase experiment concluded that the genetic material of a bacteriophage is:β DNA
Q4. In the Hershey-Chase experiment, the DNA and protein were respectively labelled with:β Β³Β²P (phosphorus) for DNA and Β³β΅S (sulphur) for protein
Q5. During bacterial transformation, only a fraction of cells take up DNA because only those cells are:β Competent
Q6. In bacteria, natural competence for transformation is usually highest during the:β Log (exponential) phase
Q7. The chemical commonly used to make E. coli artificially competent for transformation is:β CaClβ (calcium chloride)
Q8. Cotransformation frequencies for three genes are: A-C 35%, B-C 56%, A-B 15%. The most likely gene order is:β B, C, A
Q9. Lederberg and Tatum used double/triple auxotrophic bacterial strains in their conjugation experiment mainly to:β Minimise the chance of spontaneous reversion
Q10. The U-tube experiment, which showed that conjugation requires cell-to-cell contact, was performed by:β Bernard Davis
Q11. Conjugation between an FβΊ and an Fβ» cell typically results in:β Two FβΊ cells
Q12. During conjugation, the F plasmid of the donor is transferred and replicated by the:β Sigma (Ο) / rolling-circle model
Q13. The sex pilus (F pilus) used in conjugation is present on the:β FβΊ (donor) cell
Q14. Gene transfer from a donor to a recipient bacterium mediated by a bacteriophage is called:β Transduction
Q15. The process of transduction was discovered by:β Zinder and Lederberg
Q16. In a Beadle-Tatum-type pathway A β(1)β X β(2)β Y β(3)β Z, a mutant grows when supplied with X, Y or Z but not with A alone. The missing enzyme is:β Enzyme 1
Q17. The F (fertility) factor that confers donor ability in conjugation is best described as a(n):β Episome (plasmid that can also integrate into the chromosome)
Q18. In an Hfr Γ Fβ» cross, the time-of-entry (interrupted mating) technique is used to:β Map the order of genes on the bacterial chromosome
Q19. The key difference between generalised and specialised transduction is that specialised transduction:β Transfers only genes located near the prophage integration site
Q20. Match each landmark with the scientist(s) and select the correct option.β A-iii, B-i, C-ii, D-iv