The flow diagram shown below identifies possible relationships between bacterial
ID: 58311 • Letter: T
Question
The flow diagram shown below identifies possible relationships between bacterial strains in various F factor states. F-^1 right arrow F+^2 right arrow Hfr ^4 right arrow F' left arrow 3 For each of the four links in the diagram, provide a description of the events involved in the transition. Drag the appropriate labels to their respective targets Transfer of an entire F plasmid Excision of the F plasmid plus some host DNA from the chromosome Precise excision of the F plasmid from the chromosome Integration of the F plasmid into the host chromosomeExplanation / Answer
1) F- is the strain which lacks F plasmid, so the first steps suggest the conversion of F- strain to F+ strain that it acquires the F plasmid.
2) Now when the Fplasmid in the F+inside the host cell get integrated into the host chromosome then it is called as Hfr strain which means Hfr stands for (high frequency).
3) Also, if the precise excision of integrated F plasmid from the Hfr strain occurs then the again F+ strain formation results.
3) And, once after the integration, the bacterial chromosome being circular so when it starts to transfer the DNA when comes in contact with F- then the transfer do start from the origin but apart of some part of F1 plasmid the host DNA will also be started to get transfer but finally before completely transferring the integrated F-plasmid the conjugate dissociates thus the F- strain could not become the F+ strain because of interruption in the complete plasmid transfer, so it is called as F' strain.