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12.2 Conjugation, Hfr Mapping & Transduction — Test 2
Q1. The F (fertility) plasmid in bacteria is directly involved in:✓ Conjugation
Q2. Which mating gives a high frequency of transfer of bacterial chromosomal genes?✓ Hfr × F⁻
Q3. In conjugation, the cell that cannot donate DNA (the recipient) is the:✓ F⁻ cell
Q4. The key difference between an F⁺ cell and an Hfr cell is that in the Hfr cell the F factor is:✓ Integrated into the bacterial chromosome
Q5. Distances between bacterial genes determined by interrupted-mating (conjugation) experiments are measured in:✓ Minutes
Q6. In their classic experiment demonstrating conjugation, Lederberg and Tatum used:✓ Two auxotrophic (multiply mutant) strains
Q7. Recombination of chromosomal genes in E. coli is expected in which conjugational cross?✓ Hfr × F⁻
Q8. A bacterium that carries two copies of certain genes (a partial diploid) is termed a:✓ Merodiploid (merozygote)
Q9. If a gal⁺-carrying F′ plasmid also includes the nearby bio locus, conjugation can make the recipient diploid for:✓ Both gal and bio
Q10. A prophage is best defined as:✓ The DNA of a temperate phage integrated into the host chromosome
Q11. Which process is most useful for fine-scale bacterial gene mapping by co-transfer of nearby markers?✓ Generalised transduction
Q12. The site on the bacterial chromosome where bacteriophage lambda integrates is called:✓ attB
Q13. In an interrupted-mating experiment, a gene that enters the recipient earlier is:✓ Closer to the origin of transfer
Q14. In an Hfr × F⁻ cross where the order transferred is leu⁺–arg⁺–met⁺, the rarest recombinant class among leu⁺ selectants is usually:✓ leu⁺ arg⁻ met⁺
Q15. A control that rules out new mutation (rather than recombination) as the source of prototrophs when two auxotrophs are mixed is to:✓ Grow each strain separately in complete medium, then plate on minimal medium
Q16. Gene transfer requiring direct cell-to-cell contact (via a pilus) is:✓ Conjugation
Q17. Two genes are co-transduced at high frequency. This indicates that the genes are:✓ Physically close together on the chromosome
Q18. An F⁺ cell transfers its F factor to an F⁻ cell. After conjugation, the recipient typically becomes:✓ F⁺
Q19. Different Hfr strains derived from the same F⁺ strain transfer chromosomal genes starting from different points because:✓ The F factor has integrated at different chromosomal sites
Q20. Match each mode of bacterial gene transfer/term with its feature and select the correct option.✓ A-iv, B-i, C-ii, D-iii