Question

In the donor cell, discuss the DNA arrangements in F+, Hfr and F’ cells. This initial arrangement allows different things to be passed into the recipient cell – how do they differ/what gets passed?

• F+,

• Hfr

• F’

Answer 1

Ans: In bacteria Gene transfer is directional in which the bacteria which is F+ or fertility factor or called F plasmid(Extrachromosomal DNA)  tranfers it genes. F factor is also heritable and F+ bacteria are male(donor) whereas F- (recipients) are females.Males make sex pili that is needed for conjugation.So, in this type of conugation F plasmid is transferred.

Hfr: High frequency of recombination: In this the F factor gets inserted itno the chromosomal DNA with the help of some homologous regions.This cell is called as Hfr. when this DNA got tranferred into the recipient, it takes away some part of Chromosomal DNA as well.SO, now recipint have three types of DNA that is Chromosomal DNA of Donor, Plasmid DNA and their own DNA.

F`: In this type of conjugation , the inserted plasmid DNA disintegrates itself and take away some of the chromosomalgenes with itself. This kind of plasmid is called F` plasmid. When this plasmid transfers to the recipient the type of Conjugation is called as F`.