In an experiment, an F+ bacterium donates a plasmid to an F- bacterium through a conjugation pilus, converting the F- cell to F+. This horizontal gene transfer requires:
- A A bacteriophage as a vector
- B Direct cell-to-cell contact via a sex pilus ✓
- C Uptake of naked DNA from the environment
- D Insertion sequences to mobilize chromosomal genes
Explanation
Bacterial conjugation is the transfer of genetic material (plasmid or chromosomal DNA) directly from a donor to a recipient cell through physical cell-to-cell contact mediated by the sex pilus (F pilus), which is encoded by the F (fertility) plasmid. The F plasmid carries tra genes encoding the pilus and mating pair stabilization proteins. Transduction (option A) uses bacteriophage; transformation (option C) involves naked DNA uptake; transposition involves mobile genetic elements moving within or between DNA molecules. Conjugation is a major mechanism for antibiotic resistance gene (R plasmid) dissemination.
Reference: Ananthanarayan & Paniker's Textbook of Microbiology, 11th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
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