Question

Compare the F and Hfr transfer.

Answer 1

Ans :-) It is called F plasmid because it has F factor which is fertility factor. This fertility factor contains the gene required for transfer or conjugation.

F+, F- and F' cells are found in bacteria.

F+ cells :- The bacterial cells which contain the F plasmid. It is called F plasmid because it has F factor which is fertility factor. The fertility factor contains the gene required for transfer of conjugation.

F- cells :- these cells are without F plasmid. These cells act as receipient as these don't have F plasmid. So they can't donate genetic material.

F' cells :- The cells where F plasmid has disintegrated and have got some genes of host chromosome are called F' cells.

Hfr means high frequency of recombination. The cells are derivative of F+ cells where F plasmid has integrated into host chromosomal DNA.

Hfr cells are able to convert F- receipient cells to F+ but F+ cells are not able to convert F- receipient cells to F+.

Hfr cells can become F+ but F+ cells can not become Hfr.

The fertility plasmid is integrated into host cell chromosome DNA in Hfr cells while the fertility plasmid is independent in F+ cells.